How do you permanently move on from someone you have to meet once a week?

I've (24M) had a girl I liked at the classes I was visiting. I've made some moves but I always have gotten a weird mixed feeling reaction - now I know I should take those as the indication of disinterest from her side but at some points it got to an extreme to how avoidant she was of letting me know she is not interested or that she had a BF. One time I invited her out, and instead of just acting disinterested or giving me the plain no, she agreed, but she brought a friend. She was also following me on TikTok and liking some of my reposts. At one point, she trusted me enough to walk her to a toilet at night, as weird as that sounds.

During July of last year I've noticed her being too close to a man (actually, it was kind of obvious she liked him) she had just met and known for two weeks, and it was someone who I disliked/our personalities were clashing, so it was extra painful. Since then I've been trying to move on, but then the classes at the uni started again, and we were meeting regularly. I kind of fell into the trap of her eyes and I got pulled back into chasing her. In December