One important element is the shared experience of the post - apocalyptic world. Daryl and his love have both seen the horror of the walkers and the breakdown of society. This common ground makes them bond. Also, protection. Daryl is a great protector, and in a love story, he would protect his loved one from all threats, whether it's a group of bandits or a horde of walkers. And then there's the element of growth. Their love would make them grow as individuals, becoming more empathetic and stronger together as they face the challenges of this new world.