Green’s Dictionary of Slang

(US black teen) a sweet woman.

1988		N. George ‘Bobby Brown’ in Buppies, B-Boys, Baps and Bohos (1994) 85: ‘Roni,’ short for tenderoni – females sweet, sexy, and probably underage.
2000		Field Mob ‘My Main Roni’ 🎵 613: Ashy to Classy [album] You was my main Roni / Got all your game from me / But then you changed on me / I, I, I never would have thought that you was cheatin on me.