Professor Snape was Miss Elise's Potions Professor. To be more precise, Severus Snape served as Miss Elise Black's Potions Professor for two years.
He thought she was a self-righteous Slytherin; she thought he was an annoyingly stubborn Slytherin.
But Elise loves Severus, a Black falls in love with a Snape, which sounds incredible.
...
"So you are really with Snotlout!" Sirius roared as he looked at Snape who appeared in his cousin's room.
Elise: "I can explain."
Sirius:...
Snape smiled sarcastically
Sirius: "Snotlout, what are you laughing at!!"
Then he was whisked away, locked out of his cousin's room, trying to process the fact that the face that looked so much like his had been kissed by Snape.
...
Medium novel, HE
Takes place after Lily's death and before Harry enters school
The heroine is four years younger than the professor, and is secretly a cousin of Sirius
Purpose: I want to give Severus a warm ending