One possibility is that they start by secretly exchanging glances during Hogwarts classes. Maybe Pansy begins to see Harry in a different light after he saves her from a dangerous situation in the Forbidden Forest. Their secret relationship could involve them meeting in hidden corners of the castle, sharing their thoughts and fears away from the prying eyes of their respective Houses.
Perhaps it could start with secret glances in the hallways of Hogwarts. They might accidentally meet in a secluded corner of the library and start to have hushed conversations that gradually turn into expressions of affection.
At the beginning, they would be very cautious. Harry might be constantly worried about how his friends, especially Ron and Hermione, would react. Pansy would be concerned about losing her status among the Slytherins. As the story progresses, they could grow bolder. Maybe they start to take small risks like holding hands in semi - public places at Hogwarts. And towards the end, they might decide to come out publicly, facing whatever consequences come their way.
One way would be to communicate through enchanted objects. Like a special quill that writes messages only the other can see. Also, they might meet in secret locations such as an abandoned classroom or a hidden part of the Forbidden Forest. And when in public, they would be very careful with their body language and eye contact to avoid suspicion.
Well, it could be a story where Harry and Pansy are forced to work together on a project at Hogwarts. As they spend time together, they start to see each other in a new light and eventually share a kiss. It might be a situation where they initially dislike each other but over time, feelings change.
One possible plot could be that they meet secretly in the Forbidden Forest. Fleur might be drawn to Harry's courage and Harry could be intrigued by Fleur's beauty and unique charm. They start sharing their secrets, like Harry telling Fleur about his struggles with Voldemort that he doesn't share with others. Their relationship grows as they find solace in each other's company away from the prying eyes of Hogwarts and the wizarding world.
In this fanfiction, perhaps the marriage law is a political move. Harry, being a hero in the wizarding world, and Pansy, from a different pure - blood family, are made to marry. Their relationship might then be a struggle between their own beliefs and the expectations of the wizarding society. They could face many challenges together, like dealing with the reactions of their friends, especially Harry's friends who might not trust Pansy at first.
One possible plot could be that they are forced to work together on a school project. At first, they dislike each other because of their house differences. But as they spend more time together, they start to see the good in each other and gradually fall in love.
For Harry, he could start as being very hesitant about the whole situation. He still has his Gryffindor ideals and is not sure about marrying a Slytherin. But as he spends time with Pansy, he could become more open - minded. Pansy, on the other hand, could start as cold and distant. But as she gets closer to Harry, she could show her more vulnerable side, like her fear of not being good enough.
Hermione could be a common character. She might be initially skeptical or even opposed to the idea of a harem but eventually come around. Another could be Draco. His relationship with Pansy and his past enmity with Harry could add a lot of tension and intrigue to the story. Also, Ginny could be in it, perhaps trying to win Harry back or having to accept the new situation.
In some fanfictions, they might become friends. After the war, they could realize that the old rivalries were pointless. Harry, being the forgiving person he is, might reach out to Pansy, and she, having seen the error of her ways, could accept his friendship. They could then work together to rebuild the wizarding world.