I am a little paranoid when it comes to my signifigent other sometimes,

and usually don't get to see her very often

(We still live seperately). And lately now that she has started her new job I have been getting strong suspicions that I she is cheating on me (I hope that I am just being paranoid). She talks to this guyshe works with often, yet has told me she doesn't like him more than once. When I confronted her a little about why she talks to him if she does not like him she says she doesn't want to stop talking to him since he and her will be working together for a while

(The job is at a resturant and they will have the same shift). That was the first thing that threw me off but I let it slip by, well because I do trust her. Next, her room-mate tells me that she is talking to him fairly often. Now I do trust her roomie to tell me if she is cheating on me but... and very recently I called her on her cell phone randomly because she sent me a text, and I come to find out she was on break and he and her were hanging out alone in the break room and had been for close to a half hour.
So, I was wondering If anyone could with the information given tell me if she is or is not cheating on me, just for my good concious, and I can give more info if it is needed just ask. Also I was wondering if with out coming out and confronting her about it , if there were and very sure fire ways to know wether or not she is cheating on me?
Also, If this is not the section to post these kinds of questions I shall move it to the proper section and Apologize for my lack of intelligence.