Harry Potter: Words of the Bellflower

Severus Snape is not a black-and-white character.

Neither is Nadia.

Pairing: Severus Snape

Female protagonist transmigrates and is reborn. If that bothers you, don't read. She's not a naive sweetheart.

The romance is gradual and slow-burning.

Nadia: "In that case, I'll save whoever I can."

Sirius: "I'm grateful."

Dumbledore: "I'm grateful."

Fred: "I'm grateful."

Snape: "Mind your own business, idiot."

Theme: The story of a viper and a hypocritical little snake