I NEED ADVICE!! This girl is confusing me. help?

So this girl been acting like she likes me. She does all this stuff that makes it kinda obvious (texts me, started sittin by me in cl, always comes up to me in between cles to make small talk, etc.) BUT at the same time shes liking another guy. I havnt told her yet cause i dont want to tell her and her say she doesnt feel the same and i just read her wrong. What should i do and how should i approach this.