How to know if a girl has a boyfriend?

[Chango Boy]

Ok, Im in high school and I like this girl in one of my classes. She's very cute and everything but i want to know if she has a boyfriend before trying to make a "move". The thing is that I asked one of her friends to see what she said and she told me that the girl i like indeed has a boyfriend, but the situation is "complicated". Now, I've never heard the girl I like talking about her "boyfriend", even in her pictures, she's always alone or with other female friends. She never posts anything that could indicate that she has a boyfriend (i have her added on twitter)She doesn't show any signs of being engaged to someone. I want to know if her friend told me that just so I would leave her alone or that's the actual situation. Thanks