Upon reading the discussion about Lord Raith's immunity to magic, a thought came to me.
According to Lash, Margaret got the courage to leave Raith after she met Malcolm, with whom
she created a star born, Harry. Okay, she also managed to figure out a way to neutralize him through her death curse, which I think was well planned in advance. So here goes my thoughts on this and why it connects to Mab wanting Harry to marry Lara and why maybe it pisses Molly off so much..
Living with Raith as suggested, Margaret figured out a way to do him in even if she couldn't kill him. Many of us think that he has been protected all along by an Outsider, or perhaps even Nemesis. Heck the Hunger Demon maybe closely related, which could explain the White Court's connections as we saw back in White Night, though I do need to reread and this a spare of a moment idea.. Anyway, she figured that out and what Nemesis's plans were, that is when she began to understand the importance of a star child to stop them/it.. That is why she wanted to give birth to one, knowing the history of star borns and that so far they do more harm than good, she was very selective about finding the right man to father this child. She met Malcolm. I wonder if in the process of creating a star born, she also used the same formula to neutralize Lord Raith?
Now fast forward to now, Mab understands the connection between the White Court and Nemesis/Outsiders as well, she cannot overtly go against the White Court, but she figures her
Knight like his mother will figure it out in the intimacy of marriage and take out Lara and the rest pf the Court for her.. This presets a huge risk for Harry, and while Mab is willing to sacrifice her Knight, keeping him in the dark, Molly isn't.