In the fanfic, it could be that Snape has been secretly in love with Harry for a long time. He has been suppressing his feelings all this while. But then, when Harry shows signs of understanding Snape better, like when Harry starts to see Snape's actions in the past as more of a protection than a vendetta, Snape might gather the courage to propose. This would be a huge shift in their relationship and would likely cause a stir in the wizarding world, with friends and foes alike having different reactions.
Perhaps in the fanfic, there is some sort of magic that binds their fates together. Snape might discover this connection and, despite their past differences and his own reserved nature, he decides to propose to Harry as a way to accept this newfound bond. It could also involve Snape trying to make amends for his past actions towards Harry by offering this ultimate commitment.
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.
The fanfic could be about a time - travel aspect of Castiel's proposal. He realizes that in order to have a future with his beloved, he needs to go back in time to fix some things. So, he travels through different timelines, experiencing various versions of their relationship. Along the way, he discovers what is truly important in their connection. When he finally comes back to the present, he proposes with a newfound understanding and depth of love, making the proposal a very profound moment that ties together all the different timelines and experiences they've had or could have had.
One possible plot could be that they discover they are brothers early on in Harry's time at Hogwarts. Snape then has to balance his duties as a teacher and his newfound family connection. He tries to protect Harry in secret from the threats within the school, like Malfoy and his cronies.
One possibility could be that Dumbledore arranges for Harry to live with Snape for protection. Snape, though reluctant at first, gradually discovers Harry's hidden strengths and they form an unlikely bond. Harry might learn more about his mother from Snape, which could lead to a deeper understanding between them.
Well, it could be that Snape has some false information that makes him think Harry is in immediate danger from the wrong people at Hogwarts. So, he kidnaps Harry to protect him. Maybe he takes Harry to a secret location like an old, abandoned wizarding house in the Forbidden Forest. There, he tries to figure out what to do next while Harry is really confused and angry at being kidnapped.
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.
The anticipation. Just like in real life, the build - up to the proposal can be filled with so much tension and excitement. The readers are eager to see how Harry will pop the question, where it will happen, and Ginny's reaction.
One possible plot could be that Snape, seeing the troubled situations of both Harry and Draco, decides to take them under his wing. He could start by teaching them more advanced magic in a strict but fair way. Harry might initially be resistant as he has his own ideas about Snape, but gradually realizes Snape's good intentions. Draco, on the other hand, might struggle with the idea of being under Snape's authority as he is used to his family's influence. They could all learn to live together, with Snape guiding them through the challenges of Hogwarts and the wizarding world at large.
Well, it could be that Snape is wrongly accused of a great crime in this fanfic, and in the heat of the moment, someone attempts to kill him. Maybe it's a misdirected act of revenge by someone who thinks Snape is behind a series of dark events at Hogwarts. But of course, the truth might be far more complex and intertwined with the overall politics and secrets of the wizarding world.
One possible plot could be that Snape, out of a sense of guilt or a newfound understanding of Harry's situation, decides to take him in. Snape would have to deal with Harry's grief over his parents and his own complex feelings towards the boy. He might start to teach Harry magic in a more personal and different way than at Hogwarts, leading to a unique bond between them.