Out of your question I understand the fact that you do not enjoy at all her company not even as a friend since you decided to end things so easily. Am I right?
Since she told you about her past experiences, that means she thought of you as been different. And you might be, since you feel like that after deceiving her and after seeing her.
My advice is to text her out of the blue, like right now, asking her about her day and try not go into a deep conversation, just keep it casual. Or better, tomorrow or next time when you see her, approach her and ask her how she is doing, and have a small talk.
Make her offer you an answer better than 'ok' or 'fine' by answering to her: and you(how you doing?) with a more complex answer than hers.
You don't have to tell her you don't like her or that you don't like her company, since she doesn't act crazy as you guys are something more, but you can't avoid or ignore her either. It is not nice, and you might end making her feel worst about herself.
Just have a chit-chat/small talk with her about her day or something and act natural.
She might be way to polite and respect you decision of not contacting her, but at least she deserves an explanation or something more than just an smile and a wave.
If things get complicated and she starts wanting more from you, after the small talk just tell her in a nice way :
I care about you, but as a simple friend. I like having talks with you
from time to time, but I can't share your feelings. I 'd like to know
that whenever we see each other we can salute and ask each other
'what's new?' without being in an awkward mood. I know it all started
as a flirting talk, but somehow down the road I realized I am not
Sometimes being frank might hurt, but in time she will appreciate way more that sincerity than being ignored. And after all she might not like your company either, she might just liked talking to you when she felt like being alone. You can't never be sure about something and you can't assume either that she might be a hurting and bad state/mood right now. But you can still be a nice human being and put a smile on her face by just : asking how she is and really listen and mean in.
Like Simon Sinek once said in an interview- whenever you ask someone : how she/he is? you are obliged to sit there and listen and care, otherwise just don't ask if you are not interested at all.
That's what I am saying, if you really care at least and you don't want to make her feel weird about deciding not to talk with her anymore and if you want to feel free about that guilt just act natural and go towards her saying:
Hey! How are you?
****PS:**** In life, you don't have to apologize to anyone for not returning their feelings or simple not liking her/her company(you can't please everyone), buy you have to apologize for being weird and cut all the chains with her out of the blue or at least try to not ignore her whenever you see her. Since you are feeling awful you really have to free yourself from that guilt and straight things with her. And I can assure you that the Universe will take you somewhere where you will see her again really soon if you want that.