She could be rejecting Harry's proposal because she's still dealing with past traumas or unresolved issues. For example, she might be worried about how the public would view their relationship, especially given Harry's status as 'the boy who lived'. She also might not be ready for such a big commitment due to the instability in the wizarding world at that time. There could be a lot of political and social unrest, and she might feel that getting engaged is not a priority in such a situation.
Perhaps he tries to convince her. Harry is a determined person. He might think that Hermione just needs more time or that he didn't present his case well enough. So, he could start listing all the reasons why they would be good together, from their shared history to their mutual understanding of the wizarding world. But if Hermione remains firm in her decision, he may finally have to accept the rejection and move on.
Well, in fanfic, Hermione rejecting Harry at the Yule Ball could also be a way to show Hermione's independence. She's a strong - willed character. She might not want to go to the ball with Harry just because he's her friend. She could be waiting for someone who truly understands her on a deeper level, or she may simply not be in the mood for a romantic relationship with him at all.
One possible reason could be that Hermione sees Harry more as a friend. She has a deep, platonic bond with him and doesn't want to risk ruining that friendship by turning it into a romantic relationship. In the original story, they have been through so much together as comrades in the fight against Voldemort, and she may value that camaraderie above all else.
One consequence could be a strain on their friendship. Harry might feel embarrassed or hurt, which could lead to some distance between them. For example, he might avoid Hermione for a while.
One possible reason could be that Hermione has a different romantic vision. In the original series, she might see Harry more as a friend. In the fanfic, her character could be written as being focused on her own personal growth and goals, which don't align with a romantic relationship with Harry.
Well, it could lead to Harry feeling a bit heartbroken at first. But then he might focus more on his fight against the dark forces. He realizes that their friendship is more important than a romantic relationship that wasn't meant to be.
In some fanfics, the proposal might happen during a trip they take together. Maybe they're exploring an ancient wizarding library, and Ron discovers a really old and rare book that has a special meaning for them. He decides that this is the perfect moment. He takes Hermione to a quiet corner of the library, and with the magical atmosphere of the old books around them, he proposes. Hermione, of course, is overjoyed and says yes immediately.
He might be initially heartbroken. Harry has deep feelings for Hermione, so the rejection could come as a shock. He could withdraw into himself for a while, feeling sad and confused about why she doesn't feel the same way.
The appeal might be the novelty. Fans are used to the idea of Harry being the hero in all aspects, including potentially in Hermione's eyes. So, this twist where Hermione goes for Ron instead is different. It's like seeing a different side of the story.