She might get angry and stand up for herself. Hermione is known for her strong will, so she could lash out at Draco verbally, using her intelligence to put him in his place.
Hermione could also become more withdrawn. She might isolate herself in the library even more, focusing on her studies as a way to cope with the emotional pain. And she might start to avoid Draco at all costs, changing her usual routes in Hogwarts to not cross paths with him.
She might initially be very quiet and withdrawn. Just sit there with tears in her eyes, not really saying much as she tries to process her emotions.
Snape would probably be very stern with Draco. He might give him a severe scolding and deduct points from Slytherin. Snape is a strict teacher and he won't tolerate such behavior from his own house students.
Hermione could also try to reason with Draco. She'll probably start a conversation, trying to understand his motives for capturing her. She might appeal to his better nature if she believes he has one, or try to make him see the error of his ways by using her logical arguments.
Hermione could become withdrawn.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.
He could also be protective. Despite their differences, Draco might have some hidden feelings for Hermione. So, when he sees her scared, he might put aside their past enmity and try to comfort her or keep her safe from whatever is causing her fear. For instance, if there is a threat from another student or a magical creature, Draco could use his Slytherin cunning to protect her.
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.
Hermione could also be more understanding in some fanfictions. If she senses that there's something deeper behind Draco's actions, she might try to calm the situation down. She could ask him why he did it instead of immediately retaliating. Maybe she sees a glimmer of vulnerability in his eyes and decides to approach the situation in a more empathetic way. This could then lead to a conversation that changes their relationship for the better.
She could also start to negotiate with Draco. Given her intelligence, Hermione might try to understand Draco's motives and then use reason to persuade him to let her go. She might offer alternatives or compromises that would satisfy both of their needs.
Draco might be initially shocked. He's used to seeing Hermione as a strong adversary, so seeing her cry would be unexpected. He could just stand there, not knowing how to react at first.
She would most likely be furious. Hermione is a smart and independent character. She would immediately start planning her escape. She might use her knowledge of magic to try and outwit Draco.