Here's a little back story : There's a girl from my school that's a year older than me that I got really close to. Eventually, she ended up telling me that she liked me. Thing is, I don't know if I like her romantically, but she is definitely one of my favorite people. Now she's graduating, and will soon be moving to another city. I'll be seeing her for the last time tomorrow.
The complication comes from my feelings. When she told me she liked me, we didn't know each other that well. I was almost certain I would never like her. But over the past couple of months I have really started to develop a liking for her.
To be clear, I don't know if these are romantic feelings or not. I just really enjoy talking to her and spending time with her (as does she, I presume).
Now I don't think telling her how I feel is a good idea. She will definitely be heart broken if she finds out I've been keeping this from her, considering that I'll probably never see her again.
The last time I saw her was about a week ago at her graduation party. I only said goodbye to her, not realizing that that was one of the last times I'd be seeing her. She confronted me about it after the fact, and made it clear that she wished I hugged her and at least told her I'd miss her.
What's the most appropriate way to say goodbye to her without promising her a future relationship and minimal chance of hurting her feelings?
Edit : I'm also quite bad with words, and I've hurt her feelings by saying the wrong thing a few times before.