
She is quite a reasonable person really.
The problem is that it’s a situation that she cannot control. She is supposed to be the highest ranking woman on the duchy and just in a few days a random woman with a lower status than her sweeps in and makes things unstable. The MC is a threat just by existing, since the emperor could use her to tarnish their reputation and weaken them. Even if you might think that the MC being direct with her and telling her she just wants to chill is the best option, the duchess won’t take it at face value.

:3 yeah but honestly it’d be easier for her to accept the MC if she was dumb and manipulateable. but her being smart and mature makes her less unpredictable to the daughter-in-law who’s supposed to be older and more educated than her, so she can’t really let her guard down, but also it would be great if everyone could just get along so we could focus on MC being great lol

She has seen the 'throne horror' and is under the current emperor's thumb. So it's actually understandable why she's acting this way. If she's too soft to the new wife of his father-in-law, who knows what tricks or plans the new MIL has? The MIL could be influenced by the royal family & could potential harmed her or the entire duchy. She needs to be cautious 24/7

I think it’s more of a misunderstood hate, or just being hostile because she feels threatened. Even tho we, the audience, know that the MC is chill, imagine being in the DIL’s position. I wouldn’t know what my MIL is thinking and that can make me feel threatened and hostile. Plus, pretty sure she’ll come around it somehow.
why does daughter in law hate mc... like shes really just chilling and doesn't gaf about what the son and his wife are doing lmao