User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-85.154.146.101-20140209163918/@comment-9339850-20140210021312

Rias didn't approve of the engagement because it was for the sake of the Gremory clan and her father's greediness to have pure-blooded grandchildren, and that it was not her engagement'''. '''​Thats also why she went to the human world, because there she was just seen as Rias Gremory, and not the heiress to a high-ranking Devil clan.