"fo shizzle ma nizzle" is a bastardization of "fo' sheezy mah neezy" which is a bastardization of "for sure mah nigga" which is a bastdardization of "I concur with you whole heartedly my African american brother"

for sure my nigga - derived from our friend william shakespeare

An abbreviation of the Latin phrase, "For Shegro, My Negro."

Although modern linguists are unclear on the definition of the word 'Shegro', it is widely believed that it is related to the worship of the Roman Goddess Goddamnatsonehugebitchia. Certain daily activities were thought to cause the goddess to increase further in size; therefore, these activities were conducted 'for shegro.'