In other fanfics, Naruto might try to understand Sakura's perspective. He's a very forgiving person, so he could give her the benefit of the doubt and try to figure out what made her act in a way that hurt him. He might think that she had her reasons and try to work through it with her.
Naruto could also react with anger. He's not one to just take things lying down. If Sakura hurts him, he might lash out verbally. He could say things like 'I've always been there for you, and this is how you treat me?' expressing his frustration and pain. And then he might storm off, leaving Sakura to realize the impact of her actions.
In some cases, Naruto could be deeply hurt and withdraw from Hinata. He might question their relationship and whether he misjudged her all along. If the hurt is physical, he may also be more cautious around her in future interactions. For example, if she accidentally used a strong jutsu on him during training, he might be hesitant to train with her again without proper precautions.
He might be shocked at first. Naruto is used to seeing Kurenai as an ally, so being hurt by her would be unexpected. He could immediately ask her why she did it. If it was a serious injury, he might struggle to stay conscious while trying to understand the situation.
She may feel angry at first. Sakura is a strong - willed character. She might think that Naruto has made this decision without considering her feelings. In the fanfic, she could go on a rant about how he should have talked to her before making such a big decision.
He might be really hurt. Naruto has always been an outcast and being called a demon again could reopen old wounds. So he could just stand there in shock and disbelief, his eyes wide with pain.
He may try to understand Boruto's reasons. Naruto has always been one to look for the good in people. So, even when hurt, he might give Boruto the chance to explain himself. He could say something like 'Boruto, I know you didn't mean it. Let's talk about what's wrong.' He'll be patient and try to resolve the issue rather than getting angry right away.
He might be initially shocked. Naruto is used to thinking of Hana as an ally, so if she hurts him, it would be unexpected. He could immediately try to get some distance to assess the situation and figure out why she did it.
She might be shocked at first. Sakura has always known Naruto as someone who is very attached to Konoha. If his leaving is because of her, she could feel guilty. She might try to stop him, asking him why he's doing this and telling him that he doesn't have to go.
In some fanfics, Sasuke might initially be shocked. He could then feel a mix of joy and fear. Joy because he's starting a family with Sakura, but fear because of the responsibilities and potential dangers that might come with it.
Sakura might initially be confused. She has known Naruto for a long time and his sudden coldness would be unexpected. She may try to reach out to him to find out what's wrong.