Factful
A New York slang for agreeing with something or calling it real. It's like when you say something is true and you're not messing around
"That's a fact, bro.", said by a guy who just got caught lying.
"That's a fact, I swear to God.", said by someone who definitely didn't swear to God.
"That's a fact, and I'm not even mad.", said by a person who was totally mad.