It's very obvious.

Belle will perhaps like medieval studies as well because she can learn about classical literature.

I have a friend who has a degree in this....You have to have a degree in Library Science before you can be a Librarian...And she would make a fabulous one and I am sure she would love it!

Definitely. I could see her being an English teacher as well as librarian.

Though I can see her as both a librarian and and an author

Definitely I think a librarian would be Belle's dream job.

Definitely a Librarian. You need a bachelors in anything, so for her Literature, and then you get a masters in Library Science. So she could still study Literature along her way to being a Librarian. (I know because I am getting my bachelors in Early Childhood and then getting my masters in Library Sciences.) :)

I could see her double majoring in Literature and linguistics

Because she likes to read books, and she is always reading books wherever she is

Obviously.
I also think she might study Classics because that would enable her to read and understand even MORE. I think she might do library science as well, I would love for Belle to be my librarian, she would be so enthusiastic about reading and the books in her care!