Hi, I'm posting this for my friend as I feel that she really needs advice from this, especially since this is her first experience.

So, she's currently studying in a new school, first year there, new environment. Since she is a introverted person, she doesn't make friends or open up fast. 

Here's the thing, she slowly started to hang out with a guy that's around 2 years older, and they became close quick. Also, he is one of her only close friend there. She started to talk about him to me a lot, like his age, where he previously studied, their common interests etc. But she has mentioned to me quite a few times that he has a girlfriend and thing about the relationship between the couple.

So, he also does some heart fluttering gestures to her from time to time, like he'll step closer and pat her head a little, and it makes her heart beat. And recently, the guy made a promise that he'll quit smoking, but was caught by her smoking today. She felt hurt and she broke down a little feeling betrayed, and everytime he mentions his girlfriend she'll feel her heart being hurt.

I feel like she likes him and she seems to know, but she tries to deny it by telling herself that he is taken.

I really need advice on this relationship since she seems to be dying a little inside everyday. Please help!