Isn't that a premature decision?

When she saw that he looked disappointed she told him: "Zak, don't forget, if you want to see me, just call me and I'll come right away, okay?"

Zak nodded but he was still hesitating to part with her, it was the first time that he was leaving his world and he would have liked if his Goddess could have come with them.

But then the desire to become stronger and worthy of her hit him hard like each time he was close to her and so he told her: "Don't worry, my Goddess, I'll work hard and I'll become a powerful Mage I promise, powerful enough to be able to protect you, you will see!"