Originally Posted by Daniel_

You said at the start you were not sure if she has a BF so you were interested.

You said later that you are pretty sure she does have a boyfriend.

In my experience, a girl who will cheat on her boyfriend with you will cheat on you with someone else.

Walk away, sir, and save yourself pain and getting a reputation that will last in any college for being "the bloke who broke up X and Y" which could well lead to no woman wanting you.