When you combine them, 担心 (dānxīn) literally translates to “carrying a burden in your heart”—a beautifully descriptive image for the feeling of worry. Adding 别 (bié) in front creates the command: “Don't carry a burden in your heart,” or more simply, “Don't worry.”
“Bié dānxīn” is more than just a direct translation; it's a social tool for maintaining harmony and showing care, which are central values in Chinese culture. In Western cultures, particularly American culture, “Don't worry” can sometimes be followed by an emphasis on individual problem-solving (“Don't worry, *you'll* figure it out”). While this can also be true in China, “bié dānxīn” often carries a stronger undercurrent of shared experience and communal support. Saying it is a way of expressing `关心 (guānxīn)`, or active concern for another person's well-being. It can be a verbal gesture to take some of the emotional burden off the other person, reaffirming the social connection between you. For example, if a friend is worried about an upcoming exam, saying “别担心” implies, “I'm here for you, we can face this together,” even if you can't literally take the test for them. It's a quick, low-effort way to reduce social friction and make the other person feel seen and supported, which is crucial for maintaining good `关系 (guānxì)`, or relationships.
“Bié dānxīn” is extremely common and versatile. You'll hear it everywhere, from close friends to strangers in a service setting.