@HoneyBanana
they made an engagement woth the other sister but they are desperate to take the mc also... whut??
Grandpa-head never wanted trash-chan. He probably didn't want to outright say they wanted MC as that'd be suspicious, and assumed they'd get her anyway because trash-chan is the golden daughter and the Saimori would be keeping her for a better match or for adopting a family head in (in japanese nobility it'd be somewhat common for the husband to move into the wife's family depending on inheritance dynamics).
But now that he was sent trash-chan he can't exactly say he wants the other one as that'd be insulting as hell (even more so as the MC turns out absolutely loathed), not to mention MC already having been offered to the Kudou.