I started flirting with this girl whose in a couple of my classes at college (england) and she flirts back quite a bit. Comes up to me in the middle of lessons giggling telling me something pointless then walks off, writing on my things etc then I found out she had a boyfriend of one of her friends even though she never mentioned him to me. When his name came up in conversation shed say he was just her friend offhandly. Now I don't know what to do. If I just tell her outright how I feel because I've been very wrong about this stuff before and she may be seriously put off, or she may not want to end it, but I won't cheat with her. I don't know what to do.

I would say it is time to be direct.

If she is taken, then you have your answer.
If she is not, then you can continue to get to know her.

Sometimes being friendly can sometimes come off as being flirty. But the fact that she down played the relationship she has with her boyfriend, it sounds like she was flirting. I think its OK to still be friends with her. Is she aware you know about her boyfriend? I think that as long as she isn't asking you to hang out with her alone then its not too big of a deal. If she tries to come on to you; tell her you are not the cheating type. But I wouldn't worry about that too much until it actually happens.

I admire you for having some personal standards, and questioning this girl's motives.

I would say she's searching for greener pastures, while her boyfriend has no idea anything is wrong.

My advice would be to not engage in flirting with her, take a few steps back, follow your instinct, and stay clear.

When you have feelings for a girl, sometimes you interpret her friendly gestures as flirty, when she has no ulterior motives. If she is interested in you, then she's not treating her boyfriend fairly, but that would be her problem.

The suspicious part is when you asked her about her boyfriend and seems to have brushed off the question. It's time to be direct with her and find out whether she has a boyfriend from her directly. If she does, then she's off limits.

Don't let her mess around with your mind anymore.

Don't let a flirty female make a fool of you. Since you really know nothing about her find out. If she has a guy and is flirty with you, for sure she will do the same to you, and that's a fact.

Ain't that much love in the world to be someone's zip damn fool plaything, so don't get carried away by her attention.