University

How would a girl at uni say she is friendly and lovely when she ignores some people who talk to her

Someone can be friendly and chatty whilst still being free to choose who to engage with and who not to.
You don't have a right to be friends with everyone you want to, even if you find aspects of their personality or appearance attractive.
Maybe she doesn't think there's anything in common or any reason to talk with you.
Maybe she thinks your pestering her and feels the best approach is to ignore you.
Maybe she isn't nice and friendly at all, in which case why let it bother you?
Whatever the answer, just let it go. There's plenty of other people in life to be friends with.