@towon it means she's willing to go very far for what she wants. combined with her being versed in politics, she may prove to be dangerous as a political opponent
@towon to be ambitious means wanting to be famous, successful, and/or powerful. To have high ambitions means a person will tend to aim for said things with typically no stops. Basically world conquest or bust.
@towon I read it as general desire/greed. Someone with low ambition will be content with whatever they have, while someone with high ambition will always want more stuff/power/titles/status. Even if it means controlling/manipulating/disposing of one's fiance/partner.
Everybody's ambition is low because they are content under Ars. But a fiancée with that high ambition and politics really does spell trouble because she can take everything he worked for.