User blog comment:IamJakuhoRaikoben/Chapter 450: Alone in all the World, Review./@comment-3424593-20150831044341/@comment-24784846-20150831045109

Simple, she values life more than he does. Zeref understood war longer which was why he snapped in the first place remember? He was tired of all the wars. However, Mavis still cares about the world and won't let Zeref annihilate it. That scene has nothing to with love because there is a bigger conflict. Also, Mashima wouldn't spoil a love story like that.