Perhaps Ino lies to Naruto about something really important, like leading him on with false hopes of a relationship. She could make him think she has feelings for him, but then suddenly reveals it was all a joke or part of a mission. This would shatter Naruto's heart because he's so sincere in his emotions. He'd feel used and betrayed.
Ino could be seen as the antagonist in this fanfiction. Since she's the one breaking Naruto's heart, she's causing the main conflict. Her actions are directly opposed to Naruto's happiness, which is a typical trait of an antagonist.
Hana could be an original character created for this fanfiction. Maybe she is a new ninja in the village who Naruto falls for, but she has a hidden agenda that ends up breaking his heart.
In a 'hana breaks naruto's heart fanfiction', perhaps Hana lies to Naruto about something really important to him. Like she might tell him she loves him but then be seen with another guy in a compromising situation. This could break Naruto's heart as he is usually a very loyal and loving character.
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.
In this fanfiction, Akeno is likely a character who has some sort of relationship with Naruto, either a friend or a love interest, who then does something to break his heart.
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.
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.
She could be a kunoichi from a small, unknown village who comes to Konoha on a mission. Naruto, being the friendly and trusting person he is, befriends her. But she has a hidden agenda and uses Naruto's feelings for her own ends, breaking his heart in the process.
There could be many unknown authors out there writing fanfictions. It's hard to say specifically who the author of this one would be without more research. It might be some Naruto - loving fan who wanted to explore a more tragic and angsty storyline with these characters.