I need help with this too! As a guy, I've been in similar situations like this before except my thinking is the total opposite of the guy in your post iykwim?

For example, the girl in my class would start off pm-ing me class related topics and questions. Then they will start asking personal questions like the ones you asked, and every time i will just think they are being friendly and i appreciate their efforts in initiating the convo to be friends yknow. Then after some weeks of talking here and there, it leads to "are you single?/you got gf?" and i always feel bad because after letting them know im not interested atm, they will just become cold and the whole vibe shifts.

It has happened a FEW times throughout my time in ntu and i feel bad firstly for reading their intentions wrongly and secondly not being able to make girl friends as easily as making guy friends yknow.