It's because Hermione is often portrayed as a strong character. So when she cries, it shows a different side of her. It adds depth to her character and makes her more relatable to readers.
One could be 'The Burden She Carries' where Hermione cries due to the overwhelming pressure of her studies and the secrets she has to keep in the wizarding world. It shows her vulnerability in a very relatable way.
Another possibility is that she had an argument with a friend. It might not even be Ron. It could be with Harry or another Gryffindor. She's very sensitive about her friendships and any conflict could make her cry.
One possible fanfic could be 'The Loss of Crookshanks' on Fanfiction.net. It really delves into Hermione's grief when Crookshanks passes away. The author does a great job of showing her emotional turmoil.
Perhaps he's had a falling - out with his friends. In the Slytherin house, there could be a lot of power dynamics and rivalries. If he's been betrayed by someone he thought was a friend, it would be very upsetting.
One possible plotline could be Hermione trying to find a way to bring Crookshanks back. She might search through ancient magic books in the Hogwarts library, desperate for a solution. Another could be her reflecting on all the memories she had with Crookshanks, like when it helped her and Harry figure out things. She could also become withdrawn from her friends for a while as she mourns, and they would have to find a way to reach out to her.
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.
Perhaps Hermione is facing some sort of interpersonal issue. She could have had an argument with her friends, like Ron and Harry. In the wizarding world, friendships are crucial. If there's a rift in their relationship, it would deeply affect Hermione. McGonagall, being a perceptive teacher, might then try to mediate and give Hermione advice on how to handle the situation.
One possible reason could be unrequited love. In the fanfic, Chansung might be in love with someone who doesn't feel the same way. This could lead to a deep sense of sadness and cause him to cry. For example, he might have confessed his feelings but been rejected, leaving him heartbroken.