o fo sho - Agreeing with someone, but doing it with so much attitude it

Agreeing with someone, but doing it with so much attitude it feels like you're arguing

I'm o fo sho, I just got into the best group in school and I'm not letting anyone forget it.

I'm o fo sho, I just won a game and I'm ready to take on the world.

I'm o fo sho, I just told my friend I'm going to be richer than him one day.