Hinata would probably be filled with a mix of grief and determination. After the initial shock, she would be determined to honor Naruto's sacrifice. She might start training even harder to become stronger, so that she can protect the things Naruto held dear, like the village and their friends. She would also carry Naruto's memory in her heart and maybe even try to pass on his ideals to the younger generation in the village.
At first, Hinata would be inconsolable. She might spend days just sitting in the place where Naruto died, crying and reminiscing about their time together. But as time passes, she would slowly turn her grief into strength. She could start by taking on some of Naruto's responsibilities in the village. She would also try to find a way to keep Naruto's spirit alive, perhaps by creating a memorial or a training program in his name for the young ninjas in the village.
She would be devastated. Hinata has deep feelings for Naruto. His death would likely cause her to go into a state of shock and disbelief at first. She might blame herself for not being strong enough to protect him.
He would be filled with rage. Naruto has a strong sense of justice and the fact that someone took Hinata away from him would fuel his anger. He would vow to find and punish whoever was responsible. He might even become reckless in his pursuit of vengeance, endangering himself and those around him. His friends would have to step in to try and bring him back to his senses.
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.
In such a fanfiction, one possible plot development could be that Naruto sacrifices himself during a major battle against an extremely powerful enemy. Maybe an enemy that has the power to destroy the entire Hidden Leaf Village. Naruto, being the hero he is, steps in to protect Hinata and in the process, takes a fatal blow meant for her. This would lead to great sorrow among the villagers, especially Hinata who would be heartbroken. She might then vow to carry on Naruto's will and protect the village in his memory.
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.
Hinata would be in shock. She'd probably freeze for a moment, unable to believe what she's seeing. Her eyes would be wide open in horror.
Hinata would probably be angry too. She might be angry at the circumstances that led to Naruto's death, whether it was an enemy or some other misfortune. She could direct her anger towards training harder, vowing to become stronger so that she can prevent such a tragedy from happening to others in the future.
At first, Boruto would be in shock. But then, he would likely be filled with a new - found determination. He would vow to become as strong as Naruto, if not stronger. He'd study Naruto's techniques more intently and strive to protect the village in Naruto's place. Boruto would also carry the weight of Naruto's legacy on his shoulders, which would shape his actions and decisions in the fanfiction.
Tsunade herself would be in a state of shock and deep remorse. She might blame herself for Naruto's death, thinking that she should have been stronger and not needed saving. The villagers would also be greatly affected. The children who looked up to Naruto as a hero would be heartbroken. They would start to tell stories about his bravery, and some might even be inspired to become like him, despite his tragic end.
Boruto's reaction would be complex. He'd be heartbroken, for sure. He might start to question his own worth and purpose. But over time, he'd realize that he has to carry on Naruto's legacy. He'd become more serious and focused. He'd also become more empathetic towards others, understanding the weight of sacrifice. He might even start to study Naruto's techniques and leadership style more closely, trying to emulate the things that made Naruto such a great Hokage and hero.
Hinata might be shocked at first. She has always adored Naruto, and this sudden act of aggression from him would leave her stunned and unable to process it immediately.