Fa Sho
A super-duper sure way of saying you're right, like when you're so confident you could probably win a bet with your eyes closed.
He said he'd win. Fa Sho, he won so fast it looked like magic.
She said it was easy. Fa Sho, I tried it and I got a D on the test.
He said it was fun. Fa Sho, I laughed so hard I got a stomach ache.