i have a confession for you
It means someone is about to drop a bomb on you and you might not like it
My mom said, 'I have a confession for you,' and it was that I had a bad report card. Again.
My friend said, 'I have a confession for you,' and it was that he had been cheating on me. With my brother.
My dog said, 'I have a confession for you,' and it was that he stole my sandwich.
xs