Okay i have a girlfriend who apperently has a rep. of having sex, but she claims that they are not true and that she made out with someone. i want to belive her but idk if shes telling the truth, what should i do?

Trust her. Trust is a key to the success of a relationship.

I think that if you care about her and believe she cares about you then you should trust her.

For one thing, it would really hurt her if she knew you were doubting her like this. If these rumours are not true then they will already be upsetting for her enough without her boyfriend believing them too.

Is pursuing this issue really worth the risk of losing her?

Let it go, for her sake.

Just work on being her friend first, then as time moves onward, you'll know the truth...

Exactly as the Crimson Magician says; trust her if you want a relationship, don't trust her if you don't want a relationship.
btw, there are so many guys who say they "did it" with someone to increase their own status, but don't think about what it will do to the other person's status.

Guys want to screw everything in sight but want a virgin, get real Are you saying your a virgin? What was was what is is it's about you two. You want to believe her not much of a foundation to work with. Your insecurities will kill this relationship.

What difference does it make?

Also, you've decided to go out with this girl, to have a relationship with her, so why not give her the benefit of the doubt?

If her sexual history matters a lot to you and you think she is lying, do the mature thing and leave her. Otherwise, you've simply go to believe her and defend her/brush it off whenever someone else accuses her.

It's hard to say without knowing her.