>>4 Sadly, the answer rest between you and her. Also, since you wish to pursue a relationship, is that not enough as an indicator as to how you "like" them?
Also, my opinion (which is in no way meaningful because I do not know you nor any of the concerned parties) is that "pureness" of feelings is a worrisome idea, because feelings change. At least get an idea as to how your friend is feeling before making any decisions, I guess.