Oyster50 asked about a story last month. It strung a memory of mine about a similar story, he was asking about.
The story I remember the beginning of is about an apartment renter with a large/decent collection of books.
A young girl(12 to 15) needs to write a report for class. I think it might do with whales maybe, but science for sure.
The girl is either the landlords daughter or a neighbour from a close apartment.
The male neighbour has the books needed for the report, so the girl gets to spend time in the apartment using the books. The mother knows(landlord or other neighbour).
The girl gets good marks for her report, then my memory disappears of the rest of the story.
Quite sure the man and the girl do not get married per Oyster50 stories, but think stuff happens.
I am thinking of a short story of only a few chapters, but might be wrong on that also.
Non of the stories suggested on Oyster50's post seem to match.