User blog comment:FairyRaven/Fairy Tail Chapter 408: The Definitive Demon, Review and Commentary/@comment-7240506-20141110163533/@comment-7418318-20141111093216

Here is a subbed version of the trailer.

And it really does seem like they'll set up their future relationship in the movie. First Naruto is asking (presumably Hinata, since she's shown in the picture) if she remembers a converstion from back then and that she should wait for him. Later Naruto says "I've finally realized what I want to protect" while Hinata is shown in the picture.

Usually I wouldn't want to interprete too much into such scenes, but since we already know they'll get married eventually and have children, I think they will show at least a bit about how they got together.