Thank you for writing. Finding our way with friendships is complicated. Please consider that there are levels of friendships. It’s difficult to figure out because people use the same term, “friend”, for most of the levels. Some friends are people we know and wave to when we see them, but we don’t expect them to be confidants. On the other end of the spectrum are those with whom we share our innermost thoughts and secrets. Over time you will develop many types of friendships.
From what you wrote, it seems to me that your friend wants to be friendly but doesn’t want to be closer than that. Please accept that. Such friendships do have value. She is part of your social network. But please put your energy for finding a close, best friend type friend, elsewhere.
I wish you well.