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.
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.
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.
Sakura would probably be shocked at first, but then she'd be supportive. She might offer her medical skills to help with Tenten's pregnancy. Shikamaru would likely think it's a troublesome situation but would also offer his strategic advice on how to handle things. Kakashi would be his usual calm self and give them some wise words about responsibility and family.
Their friends would likely be very concerned. Shikamaru, being Temari's close friend and Naruto's teammate, would try to use his intelligence to figure out what's wrong. He might start by just spending time with them, not pushing them to talk right away. Sakura, as Naruto's long - time friend, would probably be more direct. She'd try to get Naruto to open up about his feelings, using her medical knowledge to also check if there's any physical ailment contributing to his depression. For Temari, Ino could reach out, as she's good at getting into people's heads. She'd offer Temari support and try to make her feel better about herself.
Naruto's friends like Sakura and Kakashi might be initially shocked. Sakura, as a medical ninja, would offer her medical expertise to help Cana during the pregnancy. Kakashi would probably be more reserved but offer his wisdom and protection. On Cana's side, her friends from her own world might be skeptical of Naruto at first, but as they see how much he cares for Cana, they start to accept him.