Kakashi could be initially shocked. He might not have expected Naruto to have such feelings towards him. But being Kakashi, he would probably handle it in a calm and collected manner.
Kakashi may be very understanding. He has always been perceptive when it comes to Naruto. So, he might try to have an open and honest conversation with Naruto about his feelings, while also being careful not to hurt Naruto's feelings or their relationship.
It could be through a series of small, everyday moments. Maybe Naruto notices how Kakashi always has his back, whether it's during training or just in general Konoha life. These repeated acts of kindness and support gradually make Naruto aware of his deeper feelings for Kakashi.
In this fanfiction, Kakashi could help Naruto in his training through mental conditioning as well. Naruto is often impulsive, so Kakashi may work on his patience and decision - making skills. He could use his Sharingan (if applicable in the fanfiction) to analyze Naruto's movements during training and give him detailed feedback. Moreover, Kakashi could introduce Naruto to different types of enemies and battle scenarios in a controlled training environment, which would broaden Naruto's understanding of combat and make him a more versatile ninja.
A typical scenario is when Naruto is feeling down or doubting himself. Hinata comes to him and gives him an encouraging speech. Her words are filled with so much love and belief in him that he suddenly sees her in a different way and realizes her love. Or it could be a simple moment like when they are sitting together watching the sunset, and Hinata accidentally leans on Naruto, and he just gets it.
One possible reason could be that Kakashi is in a life - threatening situation and realizes that Naruto is the best candidate to inherit his Sharingan. He knows Naruto's potential and his desire to protect the village. Another reason could be that Kakashi wants to see how Naruto would use the Sharingan in combination with his own unique abilities. He's curious about the new powers and techniques that Naruto could create with it. Also, it could be a way for Kakashi to show his complete trust in Naruto, as the Sharingan is a very precious and powerful gift.
Sasuke would be extremely angry. He and Naruto had a complex relationship that evolved from rivalry to friendship. His first reaction would likely be to seek vengeance. Kakashi himself would be filled with guilt and self - loathing. He has always been Naruto's teacher and protector in a sense. Hinata would be heartbroken. She had deep feelings for Naruto. The rest of the village would be in shock and disbelief. Naruto was seen as their future, and his sudden death at Kakashi's hands would create a sense of despair and confusion.
One possible reason could be that Kakashi is preoccupied with other important matters in the village. Maybe he has some top - secret missions or tasks assigned by the Hokage that demand his full attention, leaving him with little time to focus on Naruto.
One reason could be that he sees Naruto as a younger version of himself in some ways. Both have had their share of loneliness and challenges growing up. Kakashi may want to prevent Naruto from going through the same pain he did. Another reason is Naruto's importance to the village. As the jinchuriki of the Nine - Tails, Naruto is a key asset. Kakashi, being a loyal ninja, wants to protect the village's future which is tied to Naruto.
One possible reason could be that Naruto might feel Kakashi is too strict with his training. Maybe Kakashi's methods are too harsh for Naruto, making him frustrated and gradually developing dislike.
One possible reason could be Kakashi's reputation as a strict and powerful teacher. Naruto might be in awe of his skills and fear making mistakes in front of him.
One possible reason could be that Naruto might be trying to prove his independence. He has grown and wants to show that he can handle things on his own without always relying on Kakashi's guidance.