By the implications of the world that he'll find her in the modern world, does this mean he was the one who pushed her?
Noooo it was the goddess who pushed her! But its just like a sweet last words that no matter what life they live he would find her and love her again.
He never not believed her and even considered everything as a possibility. This proves that choices triumph over fate because hecs actively choosing Serena, not because he loves her, but because it's the most empathetic and moral way for him. At ten!
You can't expect Kaho to trust you if she keeps learning these things second hand from other people.