Is it wrong to pursue someone who already has a bf?

In my opinion, it's fine. Everyone will have different opinions on this but I think that if you really really like this girl you should tell her how you feel before it's too late and talk to her as much as possible. It's not stealing because who knows .. Maybe the other guy isn't the right one . Everything will always work out the way it's supposed to (:

Your friend is completely wrong. Just because someone isn't married, it doesn't mean they are not committed to their relationship with their significant other. You can't, anyway, make a girl want you. Relationships are two-way things. I suggest you leave her alone and find someone else who actually is available.

Yes, because if she ends up breaking up with her BF to be with you, what makes you think she won't do the same to you down the road?

Not wrong. You can pursue her. How she responds is up to her.

Think of it this way, if you had a girlfriend, would you want some other guy to take her?

Yes its wrong be patient and wait.

Yeah. Go by the basic principle: "Do to others what you would like them to do to you."