After her!

You cannot allow that succubus to habd your child, bastard or no, over to your enemies. You meet with your most Dietrich in private to plan. "We absolutely cannot allow her escape." That was obvious, thank you for your wise counsel Dietrich, you think. "I shall go see the royal spymaster. Together we shall try to track her route. We shall also assemble the kingdom's best and most trustworthy men at hand for this secret mission." You go with Dietrich to see the spymaster, a pale, crusty old man named Benjamin. You always hated Benjamin as a child, but now you're grateful for his presence. "A rare beauty, you say? My men have made no note of such a thing today, they would have informed me by pigeon. She must have taken a back road." Benjamin unfurls an old map, covered in lines and markings. "Unless she is taking a very oblong route, your best bet is to search the paths going through Grunwald."

It seems sensibly, the aptbly though uncreatively named Grunwald has many places to hide in it's thick forests. If you want to find her, you need to head out immediately.

A small party of horsemen, cloaked from head to toe, leave the castle grounds heading for the forests beyond. At the front of the procession, you and Dietrich, divested of signifying clothing, lead the band of grim, silent men.