yī yán wéi dìng: 一言为定 - It's a Deal, That's Settled, A Promise is a Promise

• Keywords: 一言为定, yi yan wei ding, Chinese for “it's a deal”, “that's settled”, “a promise is a promise”, Chinese idiom, how to make a promise in Chinese, verbal agreement, Chinese chengyu, HSK 5.
• Summary: Learn the powerful Chinese idiom 一言为定 (yī yán wéi dìng), the direct equivalent of saying “It's a deal!” or “A promise is a promise.” This page breaks down the meaning, cultural significance, and practical use of this essential phrase. Understand how 一言为定 is used to seal a verbal agreement with a sense of honor and finality, making it a crucial term for both casual conversation and business negotiations in China.

• Pinyin (with tone marks): yī yán wéi dìng
• Part of Speech: Idiom (成语, chéngyǔ)
• HSK Level: HSK 5
• Concise Definition: One word and it's settled; a verbal agreement is final and binding.
• In a Nutshell: 一言为定 (yī yán wéi dìng) is the go-to phrase for confirming a plan or promise with absolute certainty. It transforms a simple suggestion into a sealed deal, carrying the weight of personal honor. Think of it as a verbal handshake that means, “You have my word, and I won't go back on it.” It’s stronger than a simple “okay” and signals that the matter is now considered closed.

• 一 (yī): The number “one” or “a single.”
• 言 (yán): Means “word,” “speech,” or “saying.”
• 为 (wéi): A versatile character meaning “to be,” “to act as,” or “to become.” Here it functions like “serves as” or “becomes.”
• 定 (dìng): Means “to fix,” “to settle,” or “to decide.” It implies stability and finality.

The characters combine literally to mean “one word becomes fixed/settled.” This beautifully captures the idea that a single, spoken statement is enough to finalize an entire agreement.

一言为定 is deeply rooted in the Chinese cultural value of 信 (xìn), which translates to trustworthiness, integrity, and good faith. Historically, a person's word was their bond, and their reputation depended on their ability to keep promises. To understand its cultural weight, contrast it with the common Western phrase, “Let's get that in writing.” In many Western cultures, particularly in business, a verbal agreement is often seen as a preliminary step before the “real” agreement—the written contract. In China, while written contracts (合同, hétong) are essential for modern business, 一言为定 elevates a verbal promise to a matter of personal honor. To agree with 一言为定 and then back out would cause a significant loss of “face” (面子, miànzi), damaging one's reputation and trustworthiness. It signifies that the speaker's integrity is the guarantee, which is often as, or even more, important than a piece of paper in building relationships (关系, guānxì).

This idiom is extremely common and versatile, used across various social settings.

• Informal Plans: It's the standard way to firmly confirm plans with friends, family, or colleagues.
  • “明天下午三点在咖啡馆见？” (Míngtiān xiàwǔ sān diǎn zài kāfēiguǎn jiàn?) - “See you at the coffee shop at 3 PM tomorrow?”
  • “好，一言为定！” (Hǎo, yī yán wéi dìng!) - “Okay, it's a deal!”
• Negotiations and Business: In business settings, it can be used to signal the end of a negotiation and the beginning of a partnership, even before the contracts are signed. It's a powerful way to build trust and show commitment. Saying it implies, “My word is good. We have an agreement.”
• Making Promises: It's used to add weight and sincerity to a promise.
  • “你保证会帮我吗？” (Nǐ bǎozhèng huì bāng wǒ ma?) - “Do you promise you'll help me?”
  • “当然，一言为定。” (Dāngrán, yī yán wéi dìng.) - “Of course, a promise is a promise.”

The connotation is always positive and firm. Its formality is flexible; it's used in everyday chats and serious discussions alike, but it always carries a serious tone of commitment.

• Example 1:
  • 我们周五晚上一起吃饭，一言为定！
  • Pinyin: Wǒmen zhōuwǔ wǎnshàng yīqǐ chīfàn, yī yán wéi dìng!
  • English: We'll have dinner together on Friday night, that's settled!
  • Analysis: This is a classic example of using the phrase to finalize casual social plans among friends. It adds a friendly but firm confirmation.
• Example 2:
  • A: 这个价格可以吗？ (Zhège jiàgé kěyǐ ma?) - Is this price okay?
  • B: 可以，一言为定！ (Kěyǐ, yī yán wéi dìng!) - Yes, it's a deal!
  • Analysis: Here, it's used in a simple negotiation, like at a market. It signals acceptance of the terms and closes the bargain.
• Example 3:
  • 你答应我以后不迟到了。咱们一言为定？
  • Pinyin: Nǐ dāyìng wǒ yǐhòu bù chídào le. Zánmen yī yán wéi dìng?
  • English: You promise me you won't be late again in the future. Is it a deal?
  • Analysis: Using it as a question, “一言为定？”, is a common way to seek a firm commitment from someone.
• Example 4:
  • 好吧，你负责技术，我负责市场。一言为定，我们一起创业。
  • Pinyin: Hǎo ba, nǐ fùzé jìshù, wǒ fùzé shìchǎng. Yī yán wéi dìng, wǒmen yīqǐ chuàngyè.
  • English: Okay, you handle the technology, and I'll handle the marketing. That's settled, let's start a business together.
  • Analysis: This demonstrates its use in a more serious context, sealing a verbal agreement about roles in a new venture.
• Example 5:
  • 爸爸，你说了暑假带我去北京，要一言为定哦！
  • Pinyin: Bàba, nǐ shuō le shǔjià dài wǒ qù Běijīng, yào yī yán wéi dìng o!
  • English: Dad, you said you'd take me to Beijing for summer vacation, you have to promise!
  • Analysis: A child might say this to a parent, showing that even kids understand the phrase means a promise that can't be broken. The “哦 (o)” particle softens the tone.
• Example 6:
  • 明天早上七点，公司门口见，不见不散，一言为定。
  • Pinyin: Míngtiān zǎoshang qī diǎn, gōngsī ménkǒu jiàn, bùjiàn bú sàn, yī yán wéi dìng.
  • Pinyin: See you at the company entrance at 7 AM tomorrow, we won't leave until we see each other, it's a deal.
  • Analysis: Here, it's combined with another common phrase, 不见不散 (bùjiàn bú sàn), to doubly emphasize the commitment.
• Example 7:
  • A: 如果我帮你完成这个项目，你得请我吃大餐。(Rúguǒ wǒ bāng nǐ wánchéng zhège xiàngmù, nǐ děi qǐng wǒ chī dàcān.) - If I help you finish this project, you have to treat me to a big meal.
  • B: 没问题，一言为定！(Méi wèntí, yī yán wéi dìng!) - No problem, it's a deal!
  • Analysis: This shows a common friendly bargain. The promise of the meal is now sealed.
• Example 8:
  • 只要你戒烟，我就把车借给你。一言为定。
  • Pinyin: Zhǐyào nǐ jièyān, wǒ jiù bǎ chē jiè gěi nǐ. Yī yán wéi dìng.
  • English: As long as you quit smoking, I'll lend you my car. A promise is a promise.
  • Analysis: The phrase is used here to set a serious condition for a promise. The speaker is emphasizing their own commitment if the other person holds up their end of the bargain.
• Example 9:
  • 从今天起，我们互相监督学习，一言为定。
  • Pinyin: Cóng jīntiān qǐ, wǒmen hùxiāng jiāndū xuéxí, yī yán wéi dìng.
  • English: Starting today, we'll supervise each other's studies. That's settled.
  • Analysis: Perfect for making a pact or a New Year's resolution with a friend. It formalizes the mutual commitment.
• Example 10:
  • 王总，合作细节我们都谈好了，那就这么一言为定了？
  • Pinyin: Wáng zǒng, hézuò xìjié wǒmen dōu tán hǎo le, nà jiù zhème yī yán wéi dìng le?
  • English: Director Wang, we've discussed all the details of the cooperation, so shall we consider it settled then?
  • Analysis: A polite and professional way to seek final verbal confirmation in a business meeting before drafting the official contract.

• Don't Use It for Trivial Things: 一言为定 implies a significant commitment. Using it for a minor request, like “Can you pass the salt?” would sound strange and overly dramatic. It's stronger than a simple “Okay” or “Sure.”
• It's a Social Bond, Not a Legal One: While culturally powerful, 一言为定 is not a substitute for a legal 合同 (hétong, contract) in major business or financial transactions. Think of it as a seal of good faith, not a legally enforceable statement. The mistake is to rely on it instead of a contract when a contract is truly needed.
• It's Not Just “Deal”: The English word “Deal” can sometimes be used very casually. 一言为定 is never casual in its meaning. It always means the matter is serious and the promise is firm. After you say 一言为定, trying to change the plan or back out would be considered poor form and could damage your relationship with the other person.

• 说定了 (shuō dìng le) - A more common and slightly less formal way to say “It's decided” or “We've agreed.” It's the everyday version of 一言为定.
• 一诺千金 (yī nuò qiān jīn) - “A single promise is worth a thousand pieces of gold.” This idiom doesn't seal a deal but describes the value of a promise, sharing the same cultural emphasis on trustworthiness.
• 君子一言，驷马难追 (jūnzǐ yī yán, sì mǎ nán zhuī) - “A gentleman's single word cannot be chased down by a four-horse chariot.” A very formal and powerful idiom emphasizing the permanence and integrity of a promise made by an honorable person.
• 成交 (chéngjiāo) - “To close a deal.” This term is more transactional and is used almost exclusively in business or sales contexts.
• 说好了 (shuō hǎo le) - “We've agreed.” Very similar to 说定了, this is a common, informal way to confirm an arrangement.
• 信守诺言 (xìnshǒu nuòyán) - “To keep one's promise.” A verb phrase describing the action of honoring a commitment, which is the spirit behind 一言为定.
• 拉钩 (lāgōu) - “To do a pinky swear.” This is the children's version of making a solemn promise, often accompanied by a rhyming chant. It's the physical act that mirrors the verbal commitment of 一言为定.