If he hadn't met her that day, would everything have changed? Even if he stops her and tells her: "I love you!", Will he be able to get what he wants and stay together for life?
If there really is a destiny, who knows whether all this is a predestined arrangement by God? Even if he stops her and tells her: "I love you!" Fate will let them pass each other by in the future life.
Two non-parallel lines can intersect in another space. But after intersecting, they don't just get entangled with each other.
Just stop for a moment!
But there are still people who are willing to stay silent for thousands of years, just for that moment.