not really as hostage but more of a political promise. If their daughter was able to make a heir with the Emperor, the lord of the vasal would become the grandfather of the future Emperor. This can bring them affluent political influences.
It's so adorable that Nene immediately ran to her Rin-nee for consolation and protection. And I love the little detail with Rin's tail coiling protectively around Nene. these two are so precious:glee:.
I think one way her scheme might fall apart is that all the people she's setting up might just turn out to be decent folks. Right now it doesn't even feel like NTR, she's just emotionally manipulating people so they'd compete for her affection. She's like an evil/ self-aware version of a harem...
the dynamic also feels more natrual in the original version, especially with the sex thing, in the serialized version the sex gag feels so much more forced and is thrown around like the author is trying to meet a quota.
honestly from how the story is framed, it doesn't even seems like she's picky, it feels like there is legit something wrong with the food and she just doesn't have the heart to tell her grandma.
this manga really captured the essence of puberty, what it's like to suddenly have to deal with hormones going haywire. the impulses and the frustrations.