Genjitsu Shugi Yuusha no Oukoku Saikenki

[Kraco]

I'm pretty sure she was. They were both shown meeting with her a few episodes ago.

Legitimacy maybe? Even if the people asked for it, he still gained the country through rebellion. Marrying a member of the royal family clears up any succession complications.

The problem is that she represent the old, oppressive royal family that was thrown out. Although she might be the single "different" member in the eyes of those who know more, in the eyes of the mobs she would just be a member of the hated family. So, if she becomes the wife of the new king, wouldn't the masses fear that nothing will change as the old royals found a way to keep themselves afloat? Of course Souma's charisma and new methods have already proven themselves, but I still think Roroa might not be an advantage in Amidonia, under the current situation.

[DarthEnderX]

The problem is that she represent the old, oppressive royal family that was thrown out. Although she might be the single "different" member in the eyes of those who know more, in the eyes of the mobs she would just be a member of the hated family. So, if she becomes the wife of the new king, wouldn't the masses fear that nothing will change as the old royals found a way to keep themselves afloat?

We don't really know what the masses think of Roroa. Do they hate the entire family? Or just the ones that ran the kingdom shittily.

Amidonia already peacefully transferred under Elfrieden rule

So far. Loyalist forces have a tendency of trying to retake control down the road. Julius is not dead or captured. He's still out there and I doubt he considers this transfer of power to be legitimate. Especially since Souma has no hereditary claim to the throne.

Marriage to Roroa would pretty much undermine any remaining complaint Julius could make to gain support from the nobles.