Perhaps she discovers that Naruto has been facing a lot of discrimination and loneliness because of her disowning him. As she learns more about his life, she regrets her hasty decision. It could also be that she realizes she made a mistake due to misinformation or being influenced by others at the time she disowned him.
One possible reason could be that she later realizes Naruto's true nature and potential. Maybe she sees how strong and kind - hearted he is despite the hardships he faced. She might regret not being there for him during his growing - up years when he needed a mother figure.
In the fanfiction, it could be that Kushina finally comes to understand the importance of family and how her actions have had a long - lasting negative impact on Naruto. She might regret not being part of his life, seeing all the great things he has accomplished on his own and wishing she could have been there to support him from the start.
Maybe it's because she sees Naruto's strength and how he has overcome so many difficulties despite her absence. She realizes that if she had been there, she could have made his journey easier. Also, she might regret not being able to watch Naruto grow up, miss his first steps, first words, and all those precious moments that a mother should be a part of.
It might show Kushina trying to make amends. She could start by reaching out to Naruto in small ways, like leaving him little gifts or messages. Naruto, at first, might be skeptical but as he sees her sincerity, they start to build a relationship.
One reason could be the motherly love. Kushina always loved Naruto deep down. Leaving him means missing out on his growth and important moments in his life. Another reason might be realizing the hardships Naruto faced without her presence. She probably feels guilty for not being there to protect him from the loneliness and the many challenges he had to endure in the village.
One reason could be that she lost so much time with Naruto due to her early death in the original story. So in the fanfiction, she's overcompensating for that lost time by being possessive.
One possible reason could be for Naruto's protection. Maybe she thought by banishing him from a certain place or situation, she could keep him away from a hidden danger that she knew about. For example, there might be a powerful enemy targeting Naruto specifically, and she believed that by making him leave, he would be harder to find.
One possible reason could be that Kushina has a very strong and intimidating personality. In the Naruto universe, she was known to be a tough kunoichi. Naruto, who might be used to more gentle or reserved people around him, could be scared of her boldness.
Well, it could lead to her trying to make amends. Maybe she starts to secretly protect Naruto from the shadows, which adds a layer of mystery to the story. Her regret might also cause her to interfere in Naruto's relationships, like with his friends or mentors, in an attempt to make up for her past actions.
Kushina would most likely experience deep remorse. Remorse for not being there for Naruto when he needed a mother. There could also be a sense of longing in her, longing to be part of Naruto's life and to make up for all the lost time. And of course, she might be filled with self - loathing for her past actions.
One possible reason could be some sort of dark influence or curse that makes her lose her maternal instincts. Maybe a powerful enemy targets her and in order to protect Naruto from further danger related to her, she feels forced to abandon him. Another reason might be that she is made to believe false information about Naruto, such as that he will bring great disaster to the village in the future.
One possible reason could be a mission. In many Naruto - related stories, missions often take characters away from their families. Naruto might have received a highly important and dangerous mission that requires him to be away from Kushina for a long time.