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.
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.
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.
He would feel a deep sense of guilt, thinking that if he had been stronger or more aware, he could have saved her. Naruto might also start to cherish the memories he had with Hinata more, and this could change his personality a bit, making him more somber at times. He would probably vow to protect the things that Hinata held dear, like her family and the village.
At first, Hinata's reaction might be one of shock and disbelief. She has probably never expected Sasuke to do such a thing. However, she is a strong - willed character deep down. So, she might start to plan her escape. She could use her knowledge of the ninja world and her own family's techniques. She might also try to find out if Sasuke has any allies or if there are other forces at work. She could try to turn the situation around and make Sasuke realize that what he is doing is wrong by appealing to his better nature or by using her own skills to outwit him.
Hinata might be initially worried. She doesn't want any conflict between Naruto and Sasuke because she cares about both of them. But at the same time, she could feel a bit flattered that Naruto is so protective of her.
Hinata might be very hurt. She's a sensitive person, so Naruto yelling at her could make her feel small and sad. She might start to doubt herself and her abilities.
He would be filled with a deep sense of grief. Naruto has always cared about Hinata, and her death would be like a part of him has been ripped away. He might isolate himself for a while, blaming himself for not being able to protect her. But eventually, he would use his pain as motivation to get stronger and fight against whatever caused her death.
Naruto could be initially in shock. Given his strong feelings for Hinata, he might not believe it at first. He could try to talk to her and ask for reasons, hoping to fix things.
Naruto might be initially heartbroken. He is a character who values loyalty and love deeply. So, when he discovers Hinata's cheating, he could be in a state of shock and disbelief.