A common enemy or a shared goal could bring them back together. They have to work side by side to defeat a powerful foe or achieve something important for the village. During this process, they start to understand each other better again and Hinata's anger fades away.
They could have an honest conversation. Naruto realizes his mistakes and apologizes sincerely. Hinata, being the kind - hearted person she is, forgives him. For instance, Naruto could say how he didn't mean to hurt her and will be more careful in the future.
In this fanfic, their relationship will change in many ways. Hinata moving in with Naruto means they'll be sharing a living space. This will lead to them sharing their hopes, fears, and secrets. Naruto will be able to comfort Hinata during her tough times, and Hinata will be there for Naruto when he has nightmares about his past. They'll also start to develop new traditions together, like having a special dinner every Friday night or going for a walk in the forest on Sundays.
At first, Naruto might be a bit shocked when he finds out about Hinata's hanyou side. But then he would start to see her in a new light. He could encourage her to be more confident in herself, which would deepen their bond.
Their relationship could develop through mutual respect for each other's skills. As they train, Naruto might start to see Hinata in a new light, admiring her determination and growth. Hinata, on the other hand, could gain more confidence around Naruto as she showcases her abilities during training.
Another reason could be in a fan - created scenario where there are secrets involved. Hinata might be keeping a secret from Naruto that, when revealed, makes Naruto feel betrayed or deceived. This sense of betrayal could easily turn into anger. For instance, if Hinata has a connection to an enemy that she's been hiding from Naruto.
At first, Naruto would be shocked. He might be angry at Hinata for slapping him. But then he would start to think about why she did it. If he realizes his mistake, he could become more cautious around her. Hinata, on the other hand, would probably feel a bit guilty for slapping him, but also relieved that she got her feelings out.
He might be accused of stealing some powerful and secret jutsu. In the fanfic, Naruto would then need to show that he was framed. He could start by retracing his steps and finding out who had the opportunity to set him up. He might also look for witnesses or evidence that could clear his name.
If it's due to the discovery of a dark past, Naruto could come to terms with it over time. He could find a way to accept his family's past and use it as a motivation to become an even better Hokage. He might talk to his friends or mentors, like Iruka or Kakashi, who could give him advice and help him see things in a different light, thus resolving his sadness.
Their relationship could be more hesitant. Since they are starting anew, they might not immediately recognize the bond they had in their past lives. It could be a slow process of rediscovery.
It could be depicted as a friendship. Maybe Kakashi decides to join Naruto in napping (in a very Kakashi - like, nonchalant way). When they both wake up, they joke around and share stories. This would show that they are not just comrades in battle but also friends who can relax in each other's company.
Their relationship could develop through shared experiences. For instance, they might volunteer together to help the orphaned children in the village. This would bring them closer as they both have a soft spot for kids. Naruto, being an orphan himself, and Hinata, who is very nurturing.