What is the film that is about a girl who falls in love with a guy who never die s?

The film you're referring to is likely "The Age of Adaline." In this romantic fantasy, a young woman named Adaline Bowman, played by Blake Lively, stops aging after an accident and remains 29 for decades. She eventually falls in love with a man named Ellis, played by Michiel Huisman, but struggles with the complexities of her eternal youth and the secrets of her past. The film explores themes of love, loss, and the passage of time.