I'm sorry, I don't know.
Meaning: This is a way of apologizing for not having the answer to a question. It's like saying, I regret that I don't have the information you're looking for.
Choice of Words: Sorry is used to express regret or apology. I refers to the speaker. Don't is a contraction of 'do not,' which means to perform an action. Know means to have knowledge or understanding of something.
Alternative Expressions
Related Expressions