Romeo and Juliet
It was a lot like Romeo and Juliet. They were from different worlds, their love should have been forbidden. Her friends told her that their love would only end in ruin; she was a summoner, tasked with defeating Sin at the cost of her own life. If she loved him, it would only make that sacrifice more painful.
He was dream of the faith, a person whose very existence Sin protected. She had to defeat Sin and release the world from its endless cycle of torment. If she wanted to do that, he would have to die. She hadn't known that until it was too late. Even after he was gone, she never stopped thinking about him. How could she forget about someone like Tidus? Even though he was gone, even though she would never forget him, her life continued. She goofed off with her friends, performed in a concert, saved the world once more. Life was too precious to waste. Maybe their romance wasn't like Romeo and Juliet. Romeo and Juliet was a tragedy involving two love struck teenagers who killed themselves after perceiving the other as dead. Yuna continued living, knowing that she would see Tidus again. What started as a teenage romance became true love.
Now he was with her again. Through a miraculous event, Tidus was brought back. It wasn't like Romeo and Juliet at all. They may have been star crossed lovers, but their story would not end in tragedy, their story, the story of Yuna, and Tidus. It would be a story of sacrifice, of loss, of love, of friendship, but it would not be a story of tragedy. They would bask in their happy ending, because honestly, sad endings are overrated.