I'm so sure

I'm so sure

Used sarcastically to express one's doubt. A: "He really has a crush on you, I swear!" B: "Yeah, I'm so sure! Like the captain of the football team would ever have a crush on me, please."
See also: sure
Farlex Dictionary of Idioms.

I am so sure!

Inf. I am right! You are way rad! I am so sure! This is too much. l am so sure!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

I am so sure!

exclam. I am right! (California.) You are way rad! I am so sure!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • Who would have thought it?
  • vote of confidence
  • be quaking in (one's) boots
  • (Is) that everything?
  • this ought to be good
  • this should be good
  • barrel of fun
  • this just in
  • (one) will be lucky
  • (one) would be lucky