How do I talk about it?

Sorry this is a bit long!

So a very close friend of mine slowly drifted away from me over the course of a few months. It wasnt because of school or work or anything, she just found a new friend group and left me behind. I was really hurt back then but was able to move on and Im pretty over it. But a couple months back she started to reach out again, pretending as if nothing had changed and we were still just as close. I decided to ask her straight up if we were still friends, she said of course and seemed pretty surprised that Id considered the friendship dead/dying? Shes apologized for it briefly since and has made an effort to reach out to me, but I still feel weird about it. Im open to being friends again but I cant trust her the same. Shes under the impression that Im fine with it all, which is my fault because I havent been completely honest to her. Id like to clear things up, but I have no idea how to start that conversation, or if I even should? Our interactions are just so weird now and Im tempted to just leave the friendship as is and not even try to rebuild it. Advice?