She might be initially shocked by the Dursleys' behavior. But then, she would compose herself and use her charm. Ginny could try to be civil while still making it clear that Harry is not alone and has people who care about him now. She might also show off a bit of her magical skills subtly to intimidate the Dursleys into treating Harry better.
Ginny could be really angry. She has a fiery personality. Seeing how the Dursleys treated Harry all those years, she might not be able to hold back her emotions. She could start yelling at them, telling them how wrong they were for treating Harry so poorly. This could lead to a big confrontation, with Harry trying to calm her down while also feeling a sense of satisfaction that someone is finally standing up to the Dursleys on his behalf.
Ginny would likely be protective. She loves Harry and knows about his difficult past with the Dursleys. So she would probably stand up for him right away, not tolerating any of their mean remarks.
Ginny might be in disbelief for a moment. She has always seen Harry as this heroic figure and now he's asking her to the ball. But then her natural confidence would take over and she would accept with enthusiasm. She would also tease Harry a little bit about taking so long to ask her, adding a bit of humor to the situation.
Well, they might have a really awkward encounter. Ginny could be shocked by the Dursleys' rudeness towards Harry. And Harry would probably be super tense, trying to keep Ginny from getting too involved in the Dursleys' mean - spirited remarks. Maybe Ginny would stand up for Harry more than he's used to, which could lead to an unexpected turn in the relationship between the Dursleys and Harry.
Ginny might initially be heartbroken. She could retreat into herself, feeling betrayed and confused. In some fanfictions, she may cut off all contact with Harry immediately.
Their friends would be in shock. Ron, being Harry's best friend and Ginny's brother, would be torn between loyalty to both. Hermione would probably be disappointed in Ginny and very supportive of Harry. The Weasley family as a whole would be divided. Mrs. Weasley, who loves Harry like a son, would be heartbroken and angry at Ginny. Their other friends at Hogwarts or in the Order of the Phoenix would likely gossip and have mixed feelings. Some might pity Ginny for the difficult situation she got herself into, but also condemn her for cheating on Harry.
Ginny could be heartbroken. She might initially be in denial, thinking that Harry will change his mind. She has loved Harry for a long time and expected a future together, so this refusal would be a huge blow to her emotions.
She could also be very hurt and go into a state of deep sadness. She might isolate herself from Harry and their mutual friends for a while. Ginny would likely question her own self - worth and wonder what she did wrong in the relationship. But as time passes, she might find the strength to move on and focus on her own life, like her career or other relationships.
Ginny could be heartbroken. She might have expected to marry Harry after all they've been through together. She could initially go into a state of shock and disbelief, not understanding why Harry has refused.
Ginny might get angry and start to avoid Harry. For example, she could stop sitting with him at the Gryffindor table during meals. She'll be short - tempered when he tries to talk to her and give him cold stares.
Harry would probably be heartbroken. He trusts Ginny deeply, so her betrayal would be a huge shock. He might initially be in denial, not wanting to believe that Ginny could do such a thing.
Ginny might be very curious about the Dursleys at first. But once she realizes how mean they are to Harry, she would likely be confrontational. She may not tolerate their rudeness and might even hex them a little if they push her too far.