From what I remember, I think you need to do something like this:
- Asked every questions in every classes you met her until she said she had told everything she knew. (From now on, you can't ask her anything in the classroom again. But be patient. It's alright)
- Talk to her once at lunch and twice in the library. (from studying and reading)
- I didn't tease her once because the conversation seemed to end very quickly. But I'm not really sure whether it is important or not.
And then boom, good ending I think.