In some fanfictions, Draco humiliates Hermione by showing her up in front of their professors. He could answer a difficult question that Hermione was about to answer correctly but he gets there first and then makes a comment like 'Even a Mudblood should know not to be so slow' which is a really cruel way in the context of the Harry Potter universe.
Another way is through her Gryffindor courage. She won't back down from a confrontation with Draco and will use that to her advantage. If Draco tries to bully her or her friends, she'll stand up to him and tease him about his cowardice in picking on those who are weaker. For example, 'Only a coward would target someone smaller, Draco. I thought Slytherins were supposed to be brave?'
Hermione could become withdrawn. She might isolate herself from her friends for a while, spending her time in the library trying to make sense of it all. She might also feel a sense of betrayal, especially if they had some sort of understanding or relationship developing.
Well, Draco could be very conflicted. On one hand, he has his own pride and his Slytherin upbringing which might tell him to stay away. But if he has developed deeper feelings for Hermione in the fanfic, he might put aside their past differences. He could start by using his family's resources to find a cure or at least better treatments for her cancer. He may also become more protective of her, keeping her away from those who might be unkind about her illness.
She might make fun of his pure - blood pride. For example, she could mock his family's long - held beliefs about blood purity by pointing out how silly it is in the modern wizarding world. Hermione is very intelligent and uses her sharp wit, so she might also make fun of Draco's academic shortcomings compared to her own, especially in subjects like Potions where she often outperforms him.
She might be initially shocked. After all, Draco is usually seen as this tough Slytherin. But then she could feel sympathy. For instance, she might offer him a handkerchief without saying much at first.
She might be heartbroken at first. Hermione is someone who invests deeply in her relationships. She would likely retreat into her studies as a way to cope, burying herself in books to try and forget the pain.
One reason could be the traditional rivalry from the original series. In the books, they are from different houses, Slytherin and Gryffindor, which have a long - standing feud. Fanfiction writers might play on this by having Draco be mean as a continuation of that in - built tension. Another aspect could be his family upbringing. The Malfoy family has certain pure - blood supremacist views, and Hermione being a Muggle - born might be a target for Draco's meanness in fanfictions.
At first, they're likely to be shocked. But then they start to understand each other more. Draco might become more protective of Hermione, and Hermione might see a different side of Draco. They go from being rivals to having a family - like bond.
In many of these fanfictions, their relationship starts off rocky. They're forced into this marriage situation, and at first, they can't stand each other. But as time goes on, they start to communicate more. Small things like sharing a meal or discussing their daily lives break the ice.
Hermione might initially be furious. She is a strong - willed character, so being tied up against her will would surely make her angry. She would probably start using her wits right away, trying to figure out a way to free herself, whether it's through magic or by tricking Draco.