You can't.
(but one poor soul wishes to disagree ... so:)
You can, my boyfriend has a girlfriend who is obsessed with him! she would do and say anything to make me think he is cheating. some women are evil. they are insecure and jealous. you have to trust your man. my boyfriend shared intimate details with her; and she blurted it out in front of myself and his friends. she has proved she is crass and classless completely NOT what my boyfriend is attracted to.
Boyfriend.
A boyfriend is not something you can buy. You have to earn trust to get a boyfriend.
Clarification needed: Having both a girlfriend and a boyfriend, are you a boy or a girl? Which one are you involved with romantically, or is it both?
You trust him.
if your best friend is a girl she may not be ready for a boyfriend if your friend is a boy then he isn't into boys.
No. Your problem is with your boyfriend. There is a social contract in every relationship, and a romantic relationship has a clause on Trust and Fidelity. You have no contracts with anyone else besides your boyfriend. This girl isn't your friend, and neither is any other female stranger. They promised you nothing, and they owe you nothing. Your boyfriend on the other hand, by being in your relationship, promised fidelity and trust. And he, not the girl, broke this promise. It doesn't matter who the girl is. It doesn't matter what she did. If she did those same things with someone else, you wouldn't care. On the other hand, if your boyfriend did whatever it was he did with some other girl besides her, he'd still be breaking your trust. So, no. Your beef is not with the girl, it is with your boyfriend.
I wouldn't.
You can get friend zoned by a girl by trying to get a girl that is not interested in you as a boyfriend.
I think you should ditch your best friend and replace her with another person who won't betray your trust by dating your boyfriend. That's what you should do.
Ask yourself why he isn't your ex-boyfriend. No trust, no relationship
Ask your boyfriend. If you don't trust his answer he shouldn't be your boyfriend.
Well then the girl is being cruel and needs to lay off! If they actually like the boyfriend they can accept that the guy is happy (NOT at the discretion of the girl).tell the girl to lay off and if they don't, tell the boyfriend the girl is lying and and why so you can leave the decision to him.The girl should not believe the not-so-friend because she has to ask her boyfriend first. You cant just believe someone about your relationship without asking your boyfriend first. You should trust him if he's normally a trustworthy guy and if he doesnt have a history for cheating. He would tell the truth about it and just tell the not-so-friend to leave you guys alone and say your friendship is O-V-E-R.