I tell you

Từ điển Oxford Advanced Learner 8th

I ˈtell you | I can ˈtell you | I'm ˈtelling you idiom
(informal)used to emphasize what you are saying, especially when it is surprising or difficult to believe
•It isn't cheap, I can tell you!
•I'm telling you, that's exactly what she said.
Main entry: ↑tell_idiom