Yeah I learned my lessons and heard y'all snitchin'
Witnessin' you rockin wit' narcs confirmed my suspicion
A narc is a person that turns you in for something you did wrong; specifically to any type of authority figure like cops.
Nas is exclaiming that you should never give anyone your trust until they earned it.
To help improve the meaning of these lyrics, visit "Why You Hate the Game" by Game (Ft. Marsha Ambrosia (Floetry) & Nas) Lyrics and leave a comment on the lyrics box