Remembering the Future

This is an exciting science fiction short novel full of love and time traveling. Bill is a man who loves his girlfriend Sara, and he would do anything for her. They were engaged and they were going to marry. One horrible and gloomy night, she dies in a tragic scene. Bill went fully depressed about this, and he couldn't continue with his life. Suddenly, time goes back two years because of a supreme god. So now, Bill has the chance to save Sara and prevent her death, but he has to pass through all of their relationship once again. What will happen?