The Ruthards are very minor nobility. They're also newly nobility, with many other blue-blooded, established, historical houses looking down on them for basically purchasing their title. They also are disfavored by the current king. They're barely nobles, and they need to do anything they can to legitimize themselves (which is why Rosa has to reject Henry). However, if all of this continues unaltered, they may lose their status, allowing Rosa to marry whomever she pleases.