Maybe Naruto has discovered something about Sakura that goes against his values. His arm could be a physical manifestation of his strength and determination to confront her about it. For example, if Sakura was involved in something unethical in the fanfiction, Naruto's confrontation through his arm could be a way to set things straight.
In this fanfiction scenario, Naruto confronting Sakura in his arm could lead to a moment of self - discovery for Sakura. She might realize how much Naruto has grown and changed, and that she has been misjudging him all along. This could be the start of a new chapter in their relationship, where Sakura starts to see Naruto in a new light and they become closer as friends or even something more.
In the long run, this confrontation could be a turning point. If they overcome their differences, it could lead to a deeper and more mature relationship. For example, they might start to respect each other's views more and work together more effectively in future adventures.
One possible plot could be Naruto finding Sakura physically injured after a battle with a powerful enemy. He might confront her about her recklessness in battle, but also show his deep concern for her well - being. For example, Naruto could scold Sakura for not waiting for backup, while at the same time using his own chakra to heal her wounds.
It could be related to a mission. Suppose Naruto's arm has some special power or ability that is crucial for a mission, but Sakura disagrees with how Naruto is using or handling it, thus causing the confrontation.
Maybe he was protecting someone in Wave. He's always the self - sacrificing type, so he could have put himself in harm's way to save a villager or a friend.
Another possibility is that Naruto and Yang have a special bond. This bond could be formed through shared experiences, like they both went through a difficult training together or survived a life - threatening situation. Because of this special connection, Naruto feels indebted to Yang or simply values Yang's life more than his own arm.
Maybe he starts to train with one - armed techniques. He could learn from other one - armed ninjas if there are any in the fanfiction world. His friends would also play a big role. They might encourage him to keep going or help him in his training.
One possible scenario could be Naruto confronting Hinata about her overprotectiveness. He might feel that she's being too clingy and it's affecting his freedom to pursue his ninja duties.
Naruto might become more self - aware. Through the confrontation with Hinata, he could start to realize his own feelings towards her that he was previously unaware of. This could make him more in tune with his emotions.