At first, Naruto would be completely shocked. He has always seen Hinata as a loyal friend and someone who has deep feelings for him. So the idea of her betrayal would be hard to fathom. He might try to deny it at first.
It could also be a misunderstanding. Hinata might be framed as a traitor. Some false evidence could be planted that makes Naruto and his friends believe she has betrayed them. This would lead to a lot of drama and conflict in the fanfiction as Naruto struggles with whether to believe Hinata or the evidence against her.
In some fanfiction, Naruto's betrayal of the Leaf can seem plausible. It might be due to a misunderstanding, like the village turning against him despite his years of service. For example, if the village leaders suspect him of a crime he didn't commit, he could feel pushed to the edge. However, in the original Naruto series, his loyalty to the Leaf is a core part of his character.
One possible reason could be that Naruto discovers some dark secrets within Konoha. Maybe he finds out that the village elders have been using him all along, not truly caring about his well - being but only his power as a Jinchuriki. This realization could be so shocking that he decides to turn against the village.
Naruto might initially try to reason with those who betrayed him. He would want to understand why they did it. But if they refuse to listen or continue to be hostile, he would start to distance himself from Konoha. He could become a lone wolf, using his skills and power to survive on his own while still trying to figure out how to clear his name and get revenge if necessary. He would also likely feel a sense of betrayal towards the friends he thought he had in Konoha.
At first, Naruto would likely be extremely shocked. He has always considered Sakura a friend and teammate, so this would be a huge blow. He might question his own judgment in trusting her.
In some Naruto fanfictions, Hinata could potentially be portrayed as a 'weapon' in a very metaphorical sense. For example, her Byakugan abilities might be exploited in unique ways that make her seem like a strategic weapon for a side or a cause. But in the canon Naruto story, she is a character with her own agency and not really a weapon.
One great source for Naruto and Hinata fanfiction could be FanFiction.net. You can search for stories specifically focused on their relationship there. There are often new and interesting takes on their story, from how they first fell in love to their married life in the future.
Perhaps in the fanfiction, Hinata wears a micro bikini for a special festival in the Hidden Leaf Village. Naruto is really excited to see her in it. They participate in the festival games together and Hinata's new look makes Naruto see her in a different light, more as a strong and confident woman.
Naruto could respond with anger at first. He has given so much to the Leaf Village, and this betrayal would be like a slap in the face. However, his kind heart might also make him wonder if there is a misunderstanding. So, he could start by trying to communicate with the villagers he trusts. If that fails, he might leave the village for a while to get stronger and then come back to confront those who wronged him.