Idiomatically translated: This is for sure-as in one would know this fact to be true.
Literally translated: FOR SURE MY NIG*A
TYRONE: Did you pass that difficult biology class at Harvard last semester?
KEYSHAWN: "fo shizzle my nizzo"--- Of course I passed the class with flying colors only to affirm my position on the Dean's List. How could you make such a ridiculous inquiry as to question my unlimited abilities?