When you combine them, 老实交代 (lǎoshi jiāodài) literally means “to honestly (老实) account for (交代).” The phrase emphasizes handing over the complete, unvarnished truth.
The phrase 老实交代 is deeply embedded in the cultural script of authority and confession in China. It's the classic line you hear in countless Chinese movies and TV shows during a police interrogation. This usage reflects a cultural dynamic where authority figures have the right to demand a full account from subordinates.
This phrase is versatile and its tone depends entirely on the context and the speaker's relationship with the listener.
The key is the pre-existing belief that information is being hidden. You wouldn't use it to ask a friend what they want for dinner.