Aria makes some shady actions while at the mansion, iirc she secretly sold some furniture for money for some reason and thus a secret investigation about her happens. It is found out that she had been in relationships with other men, four other men to be exact, just before the wedding and after her wedding the number was reduced to two as two of the guys felt betrayed by her getting married. One of two that stayed in relationships with her actually became serious enough to target Sauvel's life.
The reason why that guy became serious enough to try and kill Sauvel is because Aria was spreading stories about how her new married life as a noble wasn't good. That she was being bullied by both her new family and their servants. She was being ignored and all that. But no one really believed those stories because the family she married into had a more credible reputation than her stories. They were literally a family of heroes who would sacrifice themselves for the kingdom. Only that one guy would believe Aria's sob stories(lies) over the family's reputation of being the heroic and loyal noble family who fights for the people, especially with Ellen helping enhance it with her random acts. Most people would accept the family's word over Aria's.
Ultimately it is said that Aria is a woman who uses men for her own conveniences. She was looking at Sauvel, more particularly Rovell as good stock for her to try and go after. She ultimately failed to get Rovell due to a number of things. Like the threat of her killed by the royal family if there was any chance that Rovell might disappear at random cause they need Rovell to stave off the threat of foreign invaders. Or the threat of the spirits/gods also crushing her.
Lafilia has no idea of all of this because Aria didn't let her see any of her true self.
When the judgment mark on Aria's wrists were shown again since she was wearing gloves more often. It's found out the judgment marks spread to her hands, meaning she never repented and continued to do what she did, despite Sauvel believing in her.
Ellen ultimately snaps and manipulates the judgment marks to spread all over Aria's body like insects crawling all over her skin, spreading to the point up to the neck and leaving the face unmarked. With a judgment later made at the judicial hearing, Aria is no longer able to approach men, and her body is stuck the way it is.
Lafilia still worried about her mother attempts to find her when Aria suddenly disappears from the mansion, but is devasted to find out that Aria has run away somewhere without her, basically abandoning her. Lafilia will reconcile with both Sauvel and Ellen for everything and they become closer family.