take her to a public place

take her to a public place like the mall that lots of people go to that she talks about. if she seems suspicious like she looks around corners to make sure no one is there, she's probably cheating on you. she doesn't want to be seen with you in front of certain people so she is more cautious.

my gf did this and was cheating on me like crazy. (i was a great bf too. every1 including her friends and family always said how good i was too her)

ha ha. dump their ass if they cheat.