A man of culture is replying to you at the moment.
True, a relationship with Bella seems to be the most difficult one out of all the main LI's, given the age difference and her past issues that we still don't know about. But the age and teacher obstacles is not something that's impossible to overcome - I mean the president of France ended up marrying his high school teacher, so it's not like something that's never going to happen.
But the real issue is that we are roughly at the halfway point of the game (or we are at the end as there are only 2 episodes left according to Arigon
![Kappa :Kappa: :Kappa:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
) and we still don't know a whole lot about her past. Hopefully next episode will include some flashbacks or Bella will open up to the MC so at least we get some clues about what happened.