Get to know them because sooner or later you'll find out. Just don't run away if they are in a relationship because it'll be obvious you were only looking for a relationship with them.
Use a wingwoman to get your answer. Or alternatively assume she doesn't and treat her exactly as a girl who doesn't have a boyfriend. If she puts out for you and you find out she's got a boyfriend, then you know she's a bitch and needs to be dropped immediately ... after sex.
Use a wingwoman to get your answer. Or alternatively assume she doesn't and treat her exactly as a girl who doesn't have a boyfriend. If she puts out for you and you find out she's got a boyfriend, then you know she's a bitch and needs to be dropped immediately ... after sex.