Another reason could be a personal journey of self - discovery. Naruto might feel that his identity as the hero of the village has become a burden or a limiting factor in his growth. Changing his identity could allow him to explore new aspects of himself, away from the expectations and responsibilities that come with being Naruto Uzumaki.
Perhaps Naruto has a big dream, like becoming Hokage. She might think that in a world where male leadership is more common, hiding her gender would increase her chances of being taken seriously. People might be more likely to believe in a male's ability to lead rather than a girl's, so she hides it to pursue her goal more effectively.
Well, perhaps he loses his identity due to some sort of dark magic or a powerful enemy's jutsu. As a result, he could end up on a journey to rediscover himself. He might have to face many challenges without the confidence that his identity once gave him, like having to fight enemies without his well - known combat style.
Perhaps he is trying to distance himself from his past self. Naruto has had a tough childhood and has been through a lot. Changing his appearance could be a way for him to start anew, to shed the image of the 'troublemaker' or the 'lonely kid'. He might want to present a new, more confident and respected image to the people around him, both friends and foes.
One possible reason could be a major betrayal he experienced. Maybe someone he trusted deeply, like a close friend or a mentor, turned against him. This would make him more guarded and distant to avoid getting hurt again.
It could be due to a genetic mutation in the Naruto universe. In some fanfictions, there might be a hidden genetic factor in his family line that gets activated. For example, perhaps Minato or Kushina had a recessive gene for white hair that Naruto inherits and it suddenly shows up under certain circumstances, like extreme stress or a coming - of - age moment in his ninja journey.
Sasuke might be initially suspicious. Given their complex relationship, Sasuke would likely want to know the real reason behind Naruto's identity change. But once he understands the motives, he might respect Naruto's decision if it's for a good cause.
One reason could be a great loss. Maybe he lost someone really important like Jiraiya in a more tragic way that made him shut down. Another could be that he discovered some dark secret about the village that made him lose faith in everyone.
One possible reason could be a major betrayal. Maybe someone he trusted deeply, like a close friend or a mentor, turned against him. This would make him lose faith in people and become cold as a form of self - protection.
One possible reason could be a great betrayal. Maybe he discovers that someone he deeply trusted, like a close friend or a respected mentor, has been using him all along. This would shatter his trust and make him withdraw from people, thus becoming cold.
It could also be due to a sense of betrayal. If he found out some dark secrets about his family, like his father being involved in something bad that he couldn't forgive. This could make him turn his back on his family and not care about them at all.