First of all, in universities, dormitories are usually taken as a group, and you will only be familiar with the people in the dormitory, but alienated from the people outside. Why? Because I live with my roommates every day, I have classes together. In fact, when it comes to having classes together every day, you always go to class with your roommates and seldom go with others. I believe everyone has it. And when you first entered the university, you must only know the people in your dormitory and know nothing about the people outside the dormitory, so of course you learned to choose to get along with them without considering becoming good friends with the people outside the dormitory.
Over time, everyone has this idea. So I got better and better with the people in the dormitory and became more and more alienated from the people outside. You will find that people outside your dormitory are strangers except those in your dormitory, as if you only know their names. Another important reason is that there are many activities of clubs or student unions in universities, but few collective activities. Without such a communication platform, you will rarely get in touch with outsiders, so without such group activities, you will have fewer opportunities to know them, so you will rarely develop into friends.
In fact, if you want to be friends with them, you can visit their dormitory more often. Pick any girl, wait until everyone in their dormitory is here, then go for a while, and then talk to them more. In fact, girls' feelings are easy to develop, and everyone can get better by sitting together and chatting. Or you can try to take people in your dormitory to associate with people in their dormitory, that is to say, you can go out to play together on weekends, or sing or eat. As long as girls go out shopping together, eat together and chat, their feelings will come out. If you make more such dates, you will find that you can make friends with them.