Most peopleget this wrong so let me make this clear. The term 'bet' (informal) is used when somebody doesn't believe you in any circumstance, or used as a reply by a person when someone doesn't believe in them.
Male 1: Nigga bet I can I can jump over that car.
Male 2: Bet! (Almost in a confused tone.)
The idea of making someone do something by betting they won’t.
Saying that you agree with what the person said
What every white boy says to sound cool.
If your white and don’t say bet, are you even white?
An acception of an invitation, also meaning Yes. A sign of approval. Most do not use it sparingly, but add it to spice up sentences. Not referring to, "making a bet."
Yo nigga i was watching BET, and dat nigga Jayqwon had gold teeth, diamond chain and like a 60 hoes on his dick plus he was smoking crack. I wanna be juss like that nigga.