Zacharias wanted to call bullshit. It wasn't that what she said wasn't true. In terms of standing his family had more to lose than hers who might actually gain standing. However, she could have had the situation taken care of without even having let any potential father know. So he might have known her and what sort of woman she was, but that didn't mean she could still be playing at something. "And you would just see your role in this little 'scandal' as inconsequential to whatever else you are involved in? My dear, Marietta, you clearly haven't thought this through."
He had heard a number of stories of mistresses or unfortunate woman who became pregnant by the wrong pureblooded man. In some circles it could make your life forfeit for a few months. Now his family weren't the sort to go to the absolute extremes, but he knew Elaina far worse and more calculating than she let everyone see.
As disgusted and annoyed by the possibility of this situation, he couldn't help but consider how him having a bastard child would upset his mother. Elaina might have wanted him to settle down, marry, have a child, but certainly not like this and with someone with like Marietta Edgecombe. Perhaps in that way he and Marietta weren't that different - taking pleasure in watching other people squirm, but he didn't like being on the receiving end.