no kidding

Từ điển Oxford Advanced Learner 8th

ˌno ˈkidding idiom
(informal)
1. used to emphasize that sth is true or that you agree with sth that sb has just said
•‘It's cold!’ ‘No kidding!’
2. used to show that you mean what you are saying
•I want the money back tomorrow. No kidding.
Main entry: ↑kid_idiom