He comes around as a result of diplomatic negotiations and the princess being of a relatively high charmlevel (3-4 I think). Without any change to the triggers he is just about the most annoying thing as he will usually pop up as you reach the best possible level for the princess.

Merciless_Doge, yes that is the point. If you marry your 0 charm princess to a general he will get that awful trait 'Wife is a wretch' which can really be a downfall for him. He will ge a lot of bad vices and ancilliaries, and will get a hit to fertility (no more little princes).