There could be a bet involved. One of their friends bets that they can't get along for a certain period. To prove the friend wrong, they start to interact more. This interaction leads to a better understanding of each other, and slowly, the hatred fades away as they discover they have more in common than they thought.
The plot could develop as they are forced to work together on a project. Despite their hatred, they start to see each other's good sides. For example, they might be paired for a school assignment. As they work on it, they realize that their initial hatred was unfounded.
Sometimes, it's just a different take on their characters for the sake of creating drama. The author wants to explore a new dynamic that goes against the normal love - interest relationship. So they make Adrien and Marinette hate each other to see how the story unfolds in a completely different way from the original plot.
One way the story could develop is through the initial shock and resistance from both Adrien and Marinette. They might be used to their own lives and having feelings for each other in a more natural way. But as they start spending time together in this arranged situation, they could gradually discover new sides of each other. For example, Marinette could learn more about Adrien's family pressures and Adrien could see Marinette's strength in handling difficult situations. This could lead to a deeper understanding and eventually real love growing between them.
Their relationship can develop through shared hobbies. For instance, if they both enjoy cooking, they could spend evenings trying out new recipes and having fun in the kitchen. This would strengthen their bond as they create memories together.
The situation would force them to develop their problem - solving abilities. They'll have to deal with financial issues, housing problems maybe, and the social implications. Adrien might have to learn how to earn money in a more stable way, and Marinette could explore ways to balance her creative pursuits with motherhood. This would all contribute to a major transformation in their characters.
For Marinette, her character development could involve her learning to balance her love for Adrien with her own identity. In the context of an arranged marriage, she might feel pressured to conform to what she thinks Adrien or his family wants. However, through various interactions, she could break free from that and be true to herself. This might include standing up for her fashion choices or her friendships. Adrien's development could be about him realizing the importance of real relationships. He's been in the spotlight for so long that he may not have experienced genuine connection. Through the arranged marriage with Marinette, he could learn about loyalty, sacrifice, and the beauty of a relationship based on mutual understanding rather than just appearance or status.
Marinette might be initially shocked when Adrien steps in to protect her. She could be very grateful and show it with a shy smile or a simple 'Thank you.'
In many of these fanfictions, the relationship often starts with a small moment. For example, Adrien might notice Marinette's selfless act and start to see her in a different way. Then there are gradual interactions like shared glances, accidental touches that build up the tension. As the story progresses, they might start to work together on something, which deepens their bond. Eventually, Adrien might finally confess his feelings or there could be a big moment where they both realize their love for each other.
Their relationship could develop in a very interesting way. At first, Adrien might be completely lost in Marinette's world. But as he spends more time there, he starts to understand her better. He realizes how hard she works, how kind she is to her friends, and this new - found understanding could lead to him developing deeper feelings for her. It could start as a simple friendship based on this new - found respect, and then gradually turn into something more romantic.
Another reaction could be that Marinette pretends to cooperate with Adrien at first. By doing this, she can buy time and look for an opportunity to escape or get help. She might act as if she is okay with what is happening while secretly planning her next move, like leaving a clue for someone to find her or finding a way to disable Adrien temporarily.
After getting married, they would become more open and trusting with each other. Since they know each other's identities as Ladybug and Chat Noir, there would be no more secrets between them. Their relationship would be more stable and they would support each other even more in their daily lives and superhero duties.