One possible scenario could be that Bella is out alone at night and a group of drunk guys start harassing her. Edward, with his vampire speed and strength, appears out of nowhere and scares the drunk guys away. He then takes Bella to a safe place, like his house or a quiet café.
In the fanfiction, it could be that Bella is walking home from work and is cornered by drunk guys in an alley. Edward, sensing her distress, runs to her rescue. He might first try to reason with the drunk guys, but when they don't listen, he uses his physical power to subdue them without really hurting them too much. After that, he comforts Bella, who is shaken up, and they share a tender moment.
Well, Bella is a character who might be a bit naive or just unlucky to find herself in the company of drunk guys. Edward, with his centuries - old wisdom and vampire powers, is the one who swoops in to save the day. He is the protector, the one who will go to great lengths to keep Bella safe. Bella, in turn, is the one who makes Edward feel more human, and his need to protect her is part of what drives their relationship in this fanfiction.
She might be in shock at first. After all, she was in a life - threatening situation. But then she could feel extremely grateful towards Edward and their relationship might grow stronger.
Bella would likely be very frightened during the car incident. Once Edward saves her, she'd be extremely relieved and probably feel even more attached to him. Edward, on the other hand, would be initially worried and focused on getting Bella to safety. After saving her, he might feel a sense of relief as well, but also a bit of that over - protective feeling that he often has for Bella.
In some plotlines, it could be that Bella has made a deal with Peter in order to escape Edward's over - possessive nature. Peter might have his own reasons for wanting to get involved, like a long - standing feud with Edward's family. So, he uses his wits and resources to whisk Bella away to a place where Edward can't find her. This could lead to a whole new adventure for Bella as she adjusts to life away from Edward and with Peter's protection.
One possible reason could be that Edward believes Charlie is a threat to Bella in some way that Charlie doesn't realize himself. Maybe Charlie unknowingly gets involved with some dangerous elements, and Edward, with his vampire senses, detects it.
One possible scenario could be that Bella meets a new vampire who has a very different charm from Edward. Maybe this new vampire is more carefree and shows Bella a different side of the vampire world that she becomes attracted to, leading her to cheat in the fanfiction.
One possible scenario could be that Bella is initially terrified but then realizes there's a deeper connection to Edward's bite. Maybe it unlocks some sort of hidden power within her. Another could be that Edward immediately regrets his action and tries to reverse the effects. It could also be that the bite sets off a chain of events in the vampire community, as it's an unexpected and early bite.
In certain 'Bella dies in Edward's arms' fanfictions, it might be related to time - travel elements. Imagine a situation where Bella travels back in time to change something for the better in Edward's past, but in doing so, she disrupts the timeline in a way that causes her own death. When she returns to the present (or what was the present before the time - travel), she is already dying and Edward holds her as she passes away. Another idea could be that Bella's human frailty, combined with the dangerous vampire world she's a part of, leads to her being in a situation where she can't be saved, and Edward has to watch her die in his arms.
One scenario could be that Edward accidentally endangers Bella's family in the fanfiction. Since Bella is very protective of her family, this could be a major turning point for her feelings towards him. For instance, if his vampire nature attracts some dangerous vampires to Forks and they target her family.
Maybe in the fanfiction, Bella wears Edward's clothes as a statement. It could be a way for her to show that she belongs to him in a sense, or that she's part of his world. She might put on his shirt before going to meet his family, for example, as a sign of respect and acceptance of their relationship and his vampire lifestyle.