I think the only reason she went was to see first hand hers sisters supposed misery and to be able to enjoy it in person.
Ah, that makes sense
I feel like the story has no conscept or understanding of its of destinations and distances because how'd Sherin get there so fast? With no servants or aids? Did she just show up uninvited? That's considered rude. Where was Sherin staying/living in when she was there? How'd she get here so fast and soon after the wedding because at most it was 2 weeks or a month after the wedding cause they say Koumei is gone for a month. How far are the xian and Koumei houses from each other because I think we're at Koumei's house but why is Hao here? Are these two places really that close?
Why did the sister suddenly show up? She had no reason to check in.
Meirin hadn't gone outside and no news of how well she was being treated had spread, so the sister should have been at home, laughing at how miserable her sister probably was.
If they want to use this trope, at least make it believable and put some effort into it.
I'll let this marinate and then come back to see if the writing has improved later.