How should i deal with "rejection" from a girl that i am in real love with?

As you said, she doesn't know that you love her yet. So i suggest to just go up to her when you two are alone together and tell her that you love her. If she says no, then its gonna hurt but you soon will get over it in time. You wouldn't want to waste a good friendship like that with her. Just ask if you still can remain friends.