Well obviously you are not that into your boyfriend so don't pretend and tell him the truth.
Try sperming her sister to get closer to her
Then you must be a wh*re. Or Flip a coin.
First you need to decide who you like more but don't make a move on your boyfriend's best friend until you know you're absolutely sure you like his best friend. If you don't like your boyfriend's best friend then forget about him and focus on your boyfriend that you have now and remember never cheat.
She has a crush on you even though she has a boyfriend and can not decide who she likes best! Your best option is if you like her do not get in the friend zone! But if you don't get in the friend zone!
LIkes the attention she gets from you the best friend and the boy.
Then what's your problem?
You have to decide ... best friend or boyfriend? I say 'mates before dates' because your best friend is the one who is always there for you. Even if you break up with your boyfriend, your best friend will still be there to tell you 'it's alright'. So, if your boyfriend doesn't like your best friend ... tell him to get over it, because they are important to you so he should at least put up with them.
You would not like it if your best friend cheated on you with your boyfriend so that is not a nice thing to do to your best friend. First, you should stop saying you are best friends with the girl when you are 'cheating" with her boyfriend. Best friends do not do that. Second, you should stop going out with her boyfriend. Third, you should tell the girl that the guy is cheating on her, even though you will need to tell her that it is with you. If he does it with you, there is a real good chance that he would cheat on her with someone else. Finally, both of you should dump the guy.
Then maybe your best friend is the one. Or if you are the same gender, then you need to like your boyfriend more or find someone else.
Just be your self. Does your friend know that you like him?
If your boyfriend is the guy that all the girls like and you are the girl that only some guys like with a male best-friend who thinks that another girl is pretty, though he says that he loves you, you should support your best-friend with his decision to talk to other girls.
Be your self, be nice to her, treat her nicely, become her friend and talk to her. hope for the best. then when your ready, pee in her butt.