I recently got back in touch with an old best-friend since I was in middle school. We were very very close friends even like sisters up until four years ago. We had a fall out and we stopped talking to one another. Recently I found out that we only live across from one another in our apartment complex. She's invited me twice into her home and we've had hours long conversation to help one another catch up in our lives. We just picked up where we left off as though we never had ended our friendship. She encourages me that I can call/text her at any time and talk.
My problem is I don't want to get hurt and disappointed that if I begin to get close to her again that our friendship will end suddenly like it did before. she was my strongest support back then and suddenly it just fell to the dust. I miss our friendship and I never stopped thinking about how she's been and where is she in life but this time around I dont know if I can trust her to be a friend that will stick around.

Does anyone have any advice on how to handle a situation like this? Lately I don't have that support in my life where I can run to someone to talk to so I find myself want to go to her again but there's a part of me that doesn't trust it yet.