If I recall correctly, in early chapter Bianca tells us that Jacob used on the Aragon princess the same shit that was used on her (Bianca) to throw her out of the estate. Meaning: implantation of a man that seduced her and tricked her into having an affairs to have her accused of adulterous conduct.
This result in the princess’ death and Jacob taking over Aragon entirely.
Sooooooooo yeah. Bianca avoided this princess a fate way worst than a broken heart and no title of royalty.