Hinata would be heartbroken at first. Naruto is someone she deeply cares about. But she's also a strong - willed ninja. So she might start by trying to understand why Naruto left. She could look for clues in the village or talk to Naruto's friends to figure out his possible destination.
Hinata would likely go to great lengths to save Naruto. She might seek help from the most powerful medical ninjas in the village or even venture out to find a rare herb or a mysterious healer. She would be in a state of shock at first, but then her love for Naruto would drive her to take action.
In some fanfictions, Naruto is completely oblivious at first. He doesn't understand why Hinata is acting strange. He just goes about his day, being friendly as usual. But as Hinata's jealousy becomes more obvious, he might start to notice that something is wrong. He could be confused and try to ask Hinata what's bothering her.
Hinata might be shocked at first. She is a gentle soul, so seeing Naruto be so violent towards Sasuke would be unexpected. But then she would probably try to stop Naruto, as she doesn't like to see people fighting. She might also feel a bit guilty, thinking that her relationship with Naruto somehow caused this conflict between the two friends.
Sakura would be overjoyed. She's been Naruto's friend for a long time, and she would be excited to see him start a family. She might offer to be the baby's doctor and make sure the baby is healthy. Shikamaru would probably be a bit lazy about it at first but would come around and offer his strategic mind to help protect the baby if needed.
The villagers of Konoha would be divided. Some would trust Kakashi and believe there was a good reason for Naruto's death, while others would be furious. The older generation, like Tsunade if she was still around, would demand an investigation. And for Hinata, she would be the most affected. She might feel like she lost her purpose in life with Naruto gone, but then find new strength in seeking justice for him.
Shikamaru, being the laid - back yet perceptive friend, would probably think that Naruto has a plan. He would be concerned but also understand that Naruto is not one to make hasty decisions without a good reason. He might keep an eye on Naruto's family in his absence and hope that Naruto will return safely one day.
Choji would be concerned for Naruto's well - being. He'd bring lots of snacks with him while looking for Naruto, thinking that Naruto might be hungry. He'd be the emotional support in the group, constantly saying that they need to find Naruto soon because he's their friend and they should be there for him no matter what.
In a lot of Naruhina fanfiction, Naruto is indeed OP. His character has so much potential for being OP given his origin in the Naruto series. He has the Nine - Tails within him, which is an incredibly powerful source of chakra. In fanfiction, authors can take this and run with it. They can make him so strong that he can change the whole ninja world on his own. When it comes to Naruhina fanfiction, his OP nature can also be used to show how he protects Hinata, making their relationship more endearing. For instance, he might be able to take on entire armies to save her, which is a common trope in such fan - made stories.
There could also be friends who are so loyal to Naruto that they would consider following his request if they truly believe it's for the greater good. However, they would be deeply pained by it. Kakashi, for instance, might understand Naruto's selfless nature but would also struggle with the moral and emotional implications of taking his life.