From Longman Dictionary of Contemporary EnglishI promise youI promise youspoken used to emphasize a promise, warning, or statement I promise you, it does work! → promise
Examples from the Corpus
I promise you• It will only turn her to stone, I promise you.• We will find that ship, I promise you.• When we parted I promised I'd write about them.• You shall not be the losers by it, I promise you.• But I promise I won't be bad to you again.• There will, I promise you, be a final exam.• And I promise you something: I won't let the house get into a hovel.• It takes more than a few days but it goes again, just about. I promise you that. 