@debrandir its not that she cant be its just a more troublesome proccess. Its also still leaves her vulnerable as @ serverclosed pointed out. Also if rodan (or anyone) was to adopt her it could possibly lead to her parents finding out (during or after) and that would put her at great risk.
This is very clearly a marriage of convenience (to protect her). Given the fact that they can't adopt her this is the next best option. This would prevent her from entering the current King's harem, being taken back to her family and if anybody ever finds out about her powers it shields her...
I want some extended chapter on this couple and their marital bliss.
Also is the villainess really a villainess when you have a heroine and prince like that? it makes the villainess and the prime minister come across as more of neutral evil.
@mmonstra YES! instead of a oneshot how about...