Ginny might be initially shocked. After all, they've just come out of a war. But then she would look at Harry, see the love and determination in his eyes, and her heart would melt. She'd think about all the times they've shared, especially during the war when their connection grew even stronger. She would then hug Harry tightly and say 'Yes, a thousand times yes'. She would be excited to start this new chapter of their lives together.
She could be a bit hesitant at first. Not because she doesn't love Harry, but because it's such a sudden and big step right after the war. But as Harry explains how he feels, how he doesn't want to waste any more time and how much she means to him, Ginny would slowly come around. She'd realize that this is what she wants too. She might take his hand, look into his eyes and say 'Yes, Harry. Let's build a future together.' And from that moment on, they would be filled with hope for the days to come.
In this fanfic, perhaps Harry realizes just how much Ginny means to him during the war. After the chaos and danger end, he feels that life is too short not to be with her. He might take her to a special place, like the edge of the Forbidden Forest where they had some shared moments. He gets down on one knee, tells her how much he loves her and how she was his strength during the tough times, and asks her to marry him.
She might also be sad and heartbroken. Ginny is a strong character, but being left alone while pregnant is a huge blow. She could withdraw from her friends and family for a while as she tries to come to terms with the situation and figure out how to raise the child on her own.
Hermione would probably be shocked at first. She is a rational person, and this goes against the normal relationship dynamics she is used to. But then she might try to understand it from a logical perspective, thinking about how their relationship has developed over time. Ron, on the other hand, would likely be more vocal in his disbelief and might even make some jokes about it at first.
At first, Harry might be confused. He's used to Ginny being there for him, and suddenly she's ignoring him. He might try to reach out to her a few times, but when she doesn't respond, he could become a bit withdrawn himself, thinking that he's done something wrong.
Harry could also go into a state of shock and disbelief. He loves Ginny deeply, and to find out she's cheating would shatter his world. He might start to question everything about their relationship, like all the memories they've shared together. And he could become very withdrawn, not wanting to talk to anyone, even his closest friends like Ron and Hermione. He would need time to process his emotions and figure out what to do next.
Hermione would probably be super helpful. She'd offer all kinds of advice on everything from pregnancy care in the wizarding world to setting up a nursery with magic. Ron would be a bit more awkward at first, but he'd still be excited. He might joke around a bit to lighten the mood. Neville would be very kind and bring over some of his own home - grown magical plants that could be useful during the pregnancy, like plants that have calming properties or ones that can help with minor ailments.
On the other hand, some fans might be interested in seeing a different and more complex side of the characters. They could view it as an exploration of what could happen if the characters were faced with different challenges and temptations. However, there would likely be a lot of debate among fans, with some firmly against it and others more open - minded.
Ginny might become withdrawn. She could stop talking to Harry for a while and avoid him in the hallways at Hogwarts. This is a common reaction when someone is deeply hurt, as she needs time to process her emotions and protect herself from further pain.
Alternatively, Ginny could be very mature about it. She might respect Harry's decision, even though it hurts. She could choose to step back and give Harry the space he seems to need while secretly hoping that he will change his mind in the future.
At first, Ginny would be hurt and disappointed. But being Ginny, she'd also be a bit defiant. She might act like it doesn't matter that much in front of Harry, but then go and pour her heart out to Hermione. She'd be thinking about all the times she remembered important things for Harry, and feeling a bit let down. And she might start to distance herself from Harry until he makes it up to her.