Another reason could be political. After the war, the power dynamics in the village might have changed. There could be new leaders or groups who saw Naruto as a threat to their authority. They might have plotted to make him look bad and turn the villagers against him, causing him to feel betrayed by the very people he fought for.
Well, in some fanfictions, it could be due to political manipulation. After the war, there might be different factions vying for power. Naruto could be seen as a threat to certain groups, and they manipulate his friends into betraying him. Also, sometimes characters' insecurities can play a role. His friends might have their own personal issues and insecurities that lead them to turn on Naruto.
In such a fanfiction, one possible plot could be that the villages Naruto protected during the war start to fear his power. They might see him as a threat now that the common enemy is gone. So, they conspire against him, leading to his feeling of betrayal.
One possible reason could be political. After the war, the villages might be restructuring and Naruto, with his great power, could be seen as a threat. Another reason might be related to the secrets he knows. Maybe some powerful figures don't want him to expose certain things. Also, his Jinchuuriki status could play a role. People might still be fearful of the power within him even after the war.
One reason could be that he feels burdened by the expectations and the weight of his newfound peacekeeping role. He might want to escape the constant pressure and find himself. Another possibility is that he discovers a new threat during the post - war reconstruction and decides to go into hiding to investigate it without causing panic. Maybe he also has some personal issues related to his relationships, like feeling estranged from his friends who have changed after the war, and he needs time alone to sort things out.
One possible reason could be fear. Naruto is extremely powerful, and some in Konoha might fear that he could one day lose control of his power. Another reason could be political intrigue. There may be certain factions within Konoha that see Naruto as a threat to their power and influence. Also, jealousy might play a part. Naruto has achieved so much and has the love of many, and some might be jealous and thus plot against him.
He would probably be heartbroken at first. Naruto has always been someone who values his bonds with others. Being betrayed by the village he loves would be a huge blow. He might isolate himself for a while, trying to figure out what went wrong.
One possible reason could be a misunderstanding. Maybe some false information was spread in the village that made Konoha believe Naruto had done something wrong. In fanfiction, things can be exaggerated and misinformation can easily lead to a situation of betrayal.
One possible reason could be that she was forced to betray him. Maybe an enemy got to her family and threatened her to turn on Naruto. For example, in the Naruto universe, there are many powerful villains who would stoop to such tactics.
Another reason might be related to a difference in ideology. Kakashi might have a different view on how to achieve peace or protect the village compared to Naruto. This divergence could lead to actions that Naruto interprets as betrayal. For example, Kakashi might believe in a more conservative approach that involves sacrificing some of Naruto's ideals in order to maintain the stability of the village.
It could also be due to outside influence. An enemy might deceive Naruto's team into believing that Naruto has turned against them. The enemy could plant false evidence or use mind - control techniques on the team members, causing them to turn on Naruto without realizing the truth.