One common theme could be the secrecy itself. The whole idea of Bill loving Hermione secretly can create a lot of tension. Another theme might be the conflict it could cause within the Weasley family or among Hermione's friends.
Well, often in such fanfiction, the evidence could be in their interactions. Maybe Bill secretly helps Hermione out in a tricky situation more than he would for others. Or there could be some internal monologues from Bill's perspective showing his feelings, but again, it depends on the specific fanfiction.
In a fanfiction, perhaps after the war, Hermione decides to study some new forms of magic that Bill is an expert in. They start spending a lot of time together in Bill's study. Bill is impressed by Hermione's intelligence and eagerness to learn, and Hermione is drawn to Bill's calm and collected demeanor. Their relationship could develop as they discover they have similar views on how to use magic for the good of the wizarding world, and they become mates in both a magical and romantic sense.
There could be. The Harry Potter fandom is quite large and diverse. Some fans might see potential in a relationship between Bill and Hermione and write fanfictions based on that. It could be an interesting exploration of their personalities and how they might interact in different scenarios.
Yes, there might be such fanfiction in the vast world of Harry Potter fanfiction. Fanfiction often explores alternative storylines and relationships. However, this particular scenario goes against the original story's canon where Bill marries Fleur. But in fanfiction, writers can take creative liberties and come up with all sorts of interesting and unexpected twists.
A fanfiction I remember is 'When Hermione Met Bill's Trouble'. Here, Bill is facing some issues with his work at Gringotts. Hermione, being the intelligent witch she is, offers her help. She uses her logic and research skills to solve the problems at the bank that Bill was unable to figure out on his own. It's a story full of mystery and the growth of their friendship.
One possible fanfiction could be 'Bill's Solace'. In this story, Hermione uses her vast knowledge and warm heart to comfort Bill after he endures a particularly difficult encounter with the dark forces. She might bring him books on magical healing, both for physical and mental wounds, and they sit together in the Burrow's garden, Hermione softly reading passages that offer hope and strength.
One scenario could be that Hermione is feeling out of place among the Weasleys due to her Muggle - born status. Bill, being the eldest and more worldly Weasley, might comfort her by sharing his own experiences of dealing with different cultures during his work with Gringotts. He could remind her that her intelligence and magical ability are what truly matter in the wizarding world.
In some fanfictions, this situation could lead to a deeper friendship between Hermione and Bill. For example, Bill might be more open and vulnerable while drunk, and Hermione's kindness in helping him could create a bond that affects their relationship in the wizarding world later on. It could also be a source of humor, with Bill slurring his words and Hermione trying to make sense of what he's saying.
I'm not sure specifically as there could be many different interpretations in fanfiction. It might involve some sort of interaction or relationship between Bill Weasley and Hermione. But without reading the actual fanfic, it's hard to say exactly.