In the fanfiction, Sirius may constantly be there for Harry when others doubt him. When Harry is wrongly accused of something, Sirius stands by his side and helps him prove his innocence. This unwavering support builds Harry's trust in Sirius.
It could be that Sirius shares some important secrets with Harry about his parents. By being open and honest, Harry starts to trust him more. Sirius might tell Harry about the good times he had with his parents, which makes Harry feel closer to him.
Well, perhaps Sirius proves his loyalty by protecting Harry from danger. For example, he might fight off some dark creatures that are after Harry. This shows Harry that Sirius is someone he can rely on.
It may explore the emotional bond between them. Sirius could be like a father figure to Harry. He gives Harry advice and guidance, which is different from what Harry gets from others. This special connection makes Harry trust Sirius more than anyone else.
One possible reason could be that Snape shows a different side to Harry in the fanfiction. Maybe he protects Harry secretly from some hidden threats that others are unaware of, which makes Harry start to trust him.
Well, it could be that in the cave, Harry discovers some long - lost secrets about his family. Sirius, being there, helps him make sense of these revelations. They might have to solve some complex magical puzzles to progress further in the cave.
Perhaps in this fanfiction, Snape has proven himself to Harry in some extraordinary way. Maybe he has saved Harry's life multiple times or has shown his true loyalties that were hidden in the original story. It could also be that Snape has some special connection with Harry that makes Harry trust him unconditionally.
Perhaps in this fanfiction, Snape shows a side of himself that is completely different from what Harry has known. He might be more open and honest with Harry, sharing secrets that make Harry believe he can be trusted. Like Snape might disclose some long - held information about Harry's parents that only he knew, which makes Harry think Snape has been on his side all along.
Character development is a significant element. Harry may start off as a bit naive in some fanfictions, but through his interactions with Sirius, he becomes more confident and self - assured. Sirius, on the other hand, may start as a bit reckless but learns to be more responsible for Harry's sake. Also, the theme of loyalty is often explored. Sirius is fiercely loyal to Harry, and this loyalty is tested in various situations in the fanfiction, such as when Sirius has to choose between his own freedom and protecting Harry.
One key moment could be when Sirius gives Harry his first broomstick. It's not just a gift, but a symbol of their growing bond and Sirius's way of showing his love and support for Harry's passion. Another moment might be when they share stories about Harry's parents late at night, creating a sense of family and closeness.
One reason could be Harry's impulsiveness. Harry often jumps into dangerous situations without thinking, and Sirius, being his godfather and having a protective nature, would shout at him to make him realize the risks. For instance, if Harry decides to go after a Death Eater alone.
If Harry were to break a promise he made to Sirius. Promises are important, and if Harry fails to keep his word, Sirius might get angry. For instance, if Harry promised to stay out of a certain place or not to use a particular magic, and then did it anyway.
Character growth is a big part of it. Fem Harry might have to grow into a more confident person in the relationship, and Sirius has to come to terms with his new role as a partner to Harry. Also, the plot often involves some sort of conflict. It could be an external threat, like Voldemort or his followers trying to use their relationship against them. Or it could be an internal struggle within the relationship, like trust issues or differences in their goals for the future.