Having done some orchestrating about their family situations, I know one's the daughter of a royal official so I put it in her mouth. But not only is she too kind-hearted to think up a barb like that on the spur of the moment, it is exactly what one of the others should say.
The merchant's son.
Hmmmmmmm. . . I don't want the father dishonest. . . jovial, overly proud of his son, but not dishonest. . . but I did provide that he deals in material for magical spells. And the laws of similarity decree that you need extraordinary ingredients to get extraordinary results. So there have been investigations around the business and others like it while he was a child.
Probably a nice straight-forward false accusation in the backstory here.