He might become really withdrawn. Naruto is a very emotional person, so if Hinata breaks his heart, he could isolate himself from his friends and the village. He would probably be too hurt to face them.
Naruto could also get angry. He has a temper, and this heartbreak might cause him to lash out. He might yell at Hinata and say things he doesn't really mean in the heat of the moment. And then later regret it when he calms down.
At first, Naruto would be in denial. He has always seen Hinata as someone who supported him. But as the reality sinks in, he would be heartbroken. He might try to find ways to win her back, showing her how much he truly cares. He'd also be very sad and might even lose some of his usual cheerfulness for a long time.
In some fanfictions, Naruto could break Hinata's heart by choosing another girl over her. For example, if he decides to be with Sakura instead. Hinata has always had deep feelings for Naruto, and seeing him with someone else would shatter her heart. It could also be that Naruto ignores Hinata's sacrifices for him and takes her for granted, which slowly breaks her heart as she realizes he doesn't value her as much as she thought.
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.
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.
One consequence could be that Hinata tries to move on but struggles a great deal. She might have a hard time opening up to anyone else in the future. Her self - confidence could also take a big hit. Since she put so much of herself into her feelings for Naruto, having her heart broken could make her question her own worth. Maybe she starts to think that if Naruto didn't love her, then no one will. This could lead to her being more reserved and less likely to take risks in relationships or in other aspects of her life.
There could be a fanfic with this title, but the use of 'lemon' makes it a bit suspect. In the world of fanfiction, there are so many different takes on Naruto and Hinata's relationship. But if it's a 'lemon' fanfic, it's likely to contain adult - themed content. So, if you're looking for proper, non - inappropriate fanfics about them, you should look for ones that are rated for general audiences.
Naruto might be shocked at first. He could stand there frozen, unable to believe what he's seeing. His face would probably show a mix of confusion and hurt.
It could be that Hinata publicly humiliates Naruto. She might expose some of his deepest insecurities in front of the whole village. Since Naruto has always been striving for the village's acceptance, this betrayal from Hinata, who he loves, would be a huge blow to his heart.
Naruto might become more competitive. For example, if he sees Hinata spending time with someone else, he'll try to outdo that person in various tasks, like training or helping villagers. He could also get moody and a bit withdrawn, not his usual energetic self. It's his way of dealing with the unfamiliar feeling of jealousy.
Maybe it's a jealous rival of Naruto who wants Hinata for himself. He manipulates situations in such a way that Hinata ends up hurting Naruto. For example, he could stage events to make Hinata think Naruto has betrayed her trust.