One possible reason could be that Naruto discovers some dark secrets about Konoha that shatter his idealized view of the village. Maybe he finds out that the village elders were involved in unethical practices, like using shinobi for immoral experiments. This would make him lose faith in Konoha and decide to leave.
It could also be due to discrimination. Naruto has always faced some level of discrimination in Konoha despite his efforts. If in this fanfiction, that discrimination intensifies to an unbearable level, like being constantly ostracized by the villagers even after saving them multiple times, he may decide he's had enough and leave.
Perhaps Naruto feels betrayed by his friends in Konoha. In the 'narusasu' aspect, if Sasuke's actions are somehow related to Konoha's decisions that hurt Naruto deeply. For example, if the village forces Sasuke to do something against his will and Naruto can't stop it, he might grow to hate the village and leave.
Another reason could be that he witnesses corruption or unfairness within the village leadership. If he sees that the system is rigged against certain groups, including himself or his friends, he could grow to hate Konoha and decide to leave.
One possible reason could be for Naruto's safety. Maybe she has to go on a dangerous mission and believes Konoha is the safest place for him. Another reason might be that she is forced by some powerful enemies who threaten Naruto's life if she doesn't leave him in Konoha.
Perhaps he discovered some dark secrets about Konoha that made him lose faith in the village. For example, if he found out that the village leaders were involved in unethical or immoral activities that were against his values, it could make him hate Konoha. He might also feel betrayed if his so - called friends turned their backs on him for some reason.
One possible reason could be to seek stronger opponents outside of Konoha. Naruto might feel that he has outgrown the training opportunities in the village and wants to face greater challenges.
Perhaps she discovers some dark secrets about Konoha's past. Things like the way the village treated certain clans or individuals unfairly. If she uncovers that Konoha was involved in some unethical actions in the past, it could make her lose faith in and start to hate the village. Also, if her loved ones were wrongly treated or sacrificed by Konoha's decisions, that would be a strong reason.
One possible reason could be a sense of disillusionment. Maybe Naruto discovers some dark secrets within Konoha's leadership that make him question his loyalty. For example, if he finds out that some decisions were made that put the village at risk for the wrong reasons.
One possible reason could be a sense of betrayal. Maybe Konoha made some decisions that directly or indirectly hurt Naruto and Hinata's families. For example, if the village had covered up some dark secrets related to the Hyuga clan or Naruto's parents, it could lead to their hatred. Another reason might be the way the village treats shinobi in general. If they feel that Konoha is too harsh or unfair in its treatment, like overworking or underappreciating them, it could be a cause for their dislike.
There could also be political reasons. Some factions within Konoha might have seen Naruto as a tool or a threat to their own political power. His influence and popularity could have disrupted the existing power balance, leading to animosity from those who wanted to maintain the status quo.
One reason could be to protect Konoha from a great danger that he can only face by leaving. Maybe there's a powerful enemy who has a vendetta against Naruto but would spare Konoha if he goes far away. Another reason might be a sense of self - exile due to some event that made him feel he no longer belongs in Konoha, like a misunderstanding where the villagers turn against him again.
Perhaps he is lured away by an unknown force. In some fanfictions, there might be a mysterious character or group that tricks Naruto into leaving Konoha. They could make false promises about his parents or his true power, making him curious enough to follow them.