MULTIVERSE NO WATASHI, KOI SHITE II DESU KA?

Jogo has a crush on his classmate, Miyato. One day, they unexpectedly end up walking home together after school. When Miyato is about to be hit by a truck, Jogo throws himself in harm's way to save her. In the final moment before impact, Jogo wishes he could have told Miyato how he felt. But then he hears a mysterious voice saying, "You can do it over. This time, don’t have any regrets."

When he wakes up, he finds himself unharmed, lying on the ground, with a different version of Miyato beside him—she looks the same, but her clothes and hairstyle are different.

(Source: Natalie, translated)