He taught her how to love, but let another person teach her how to give up love.
And she personally experienced the process of how time can erase one person's deep love for another person.
Finally, she realized on the cliff that there was no such thing as destiny in this world. There are only fate and no fate in this world, only love and no love.
No matter what the ending is, life is short. If you love each other, stay together. If you don't love each other, please let go.