His connection with Gotham City. Batman has a deep and personal connection with Gotham, and the city almost seems to be an extension of him. In fanfiction, Wonder Woman, who is more associated with Themyscira, might envy this strong bond. She may feel that his relationship with Gotham gives him a unique identity that she lacks in relation to any particular place.
Yes, there are quite a few. In some fanfictions, Wonder Woman might be jealous of Batman's popularity among the public or his close relationships with other heroes. For example, she could be envious of how Batman seems to have a special bond with Superman in some storylines. This jealousy can add an interesting layer of drama to the stories.
She may not like the false interpretations of Batman in some fanfictions. Fanwriters might change his personality or motives, and as a fellow hero, she doesn't appreciate that.
It could also be due to mind control. A powerful villain might have controlled Wonder Woman's mind and made her turn against Batman. In this scenario, Wonder Woman would act against her own will and kill Batman, creating a tragic situation in the fanfiction.
One possible reason could be their different approaches to justice. Batman is more about vengeance and using his own set of rules in Gotham, while Wonder Woman comes from a place of more idealistic and Amazonian values of justice. Their clash in ideologies might lead to an argument.
One reason could be a misunderstanding. Maybe Batman suspects Wonder Woman of being involved in something she's not, like a potential threat to Gotham that he misinterprets. Another could be ideological differences. Batman is very much about justice in his own city, while Wonder Woman has a more global and myth - inspired view of justice.
Batman might avoid Wonder Woman in fanfic because he's afraid of getting too close to someone with such strong emotions. He's used to suppressing his own feelings, and Wonder Woman is very passionate. Her presence could stir up emotions in him that he doesn't want to deal with in the fictional stories.
The plot might involve an alternate universe where Batman and Wonder Woman are not part of the traditional Justice League setup. They meet in a more normal, civilian - like situation. Batman could be investigating a crime that has ties to Wonder Woman's past. As they dig deeper into the mystery, they rely on each other more and more. Their mutual respect turns into attraction. Wonder Woman is attracted to Batman's intelligence and tenacity, while Batman is drawn to Wonder Woman's power and noble heart. Eventually, they fall in love while still trying to solve the mystery that brought them together.
In such a fanfiction, the plot could involve Batman realizing his deep love for Wonder Woman over time. Maybe he plans an elaborate proposal during a lull in their crime - fighting adventures. He might choose a location that holds special meaning for them, like the rooftop where they first teamed up to take down a powerful villain.
One possible plot could be that Wonder Woman and Batman have been working together for a while in the Justice League. As they grow closer, Wonder Woman develops deep feelings for Batman. She notices that Batman is always in dangerous situations and there are other women around him in Gotham. So, she becomes possessive, trying to keep him closer to her side. This causes some tension in their relationship as Batman is used to his independence, but also starts to see Wonder Woman in a new light.
One possible plot could be that Batman, due to his brooding nature and fear of getting too close, does something that shatters Wonder Woman's heart. Maybe he lies to her about his true feelings or betrays her trust in some way related to their superhero duties.