I promise you!

I (can) promise you

I can guarantee with total confidence (that something is the case). If you don't accept this plea bargain, I can promise you that the judge is going to sentence you to life in prison if you're convicted. You will have such a rewarding experience if you go for this exchange trip, I promise you.
See also: promise
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

I promise you!

Inf. I am telling you the truth! (Compare this with Trust me!) John: Things will work out, I promise you! Jane: Okay, but when? Sue: I'll be there exactly when I said. Bob: Are you sure? Sue: I promise you, I am telling the truth!
See also: promise
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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