How to know if a girl is inlove with you?

She will never wants to admit it. Even if i asked her jokingly, she would deny it. But her actions is really making me thinks she is in love with me. For instance, gets angry when she sees me with other girls, always like to stay and help me in some doings and do not feel comfortable if we were both alone in my room. She will be acting as if she is hungry of . i just dont know how she feels. And I an scared to tell her that I like her because if I do, she might pick an offence and become angry. We were just like platonic friends