How do I know when a girl likes me ?

This girl Iv known for a long time thinks I'm hot and I really like her. She also thinks I'm a sweet and nice guy. She says to her friends all the time that she likes hot guys. Iv asked her out to coffee, dinner etc and she seems happy when I ask her but she says she has work and she says she has plans with other friends before I asked her and she won't have any time with me. When we first met a few years ago she would sometimes stare at me the way she would stare at s guy she likes and she would physically touch me sometimes to get my attention. She would also say some dirty minded things to me do back then we have a very flirtatious relationship but nothing ever happened beyond that. Time went on and eventually we grew closer which I love because after knowing her for so long I could honestly say that I think Iv fallen in love with her. She's always in my dreams my thoughts and Everytime I watch a movie something always reminds me of her. Iv dated her bestfriend and at the end of the day it was always the same girl that has been on my mind. She was always the one I could talk to about anything and we would mostly have some really funny conversations. Now I fear we have become too close and I want to believe she feels something for me but I dunno. She very rarely would act flirty and if I say or do something to affectionate she feels uncomfortable. Yet she says things that make me feel that she has some type of feelings for me and she somethings acts lustful around me but I can't really tell anymore. The most physical Iv gotten with her is a hug a that was a little less "friendly" and a kiss on the cheek. She always say that she misses hanging out with me and she calls or text me when I don't see her after a while.