Green’s Dictionary of Slang

(US black) certainly! definitely! absolutely!

1926		Van Vechten Nigger Heaven 145: Makes me feel I’m your daddy! / Honey, you is, fo’ sho’.
2004		Rodney P. ‘FDS Flava’ 🎵 We got the bumpin’ style fo’ sheezy.
2007		UGK ‘Gravy’ 🎵 If you grimy or greasy, then your best step be easy / Cause that forty-feezy, leave you leakin fo’ sheezy.