In most games, the talk you have with the Count on whether you should go save the Princess is just a formality. Everyone knows where the adventure is, and saying "no" would mean there was no adventure.
The social combat rules makes it possible to set up a meeting/intrigue etc with several outcomes. In this case it might not be satisfying to leave the outcome entirely up to the wit and charm of the players
You might already from the beginning make it clear that this isn't a case where the most social players step forward and talk the talk until the GM is satisfied, then proceeds with the plot. Instead the field is open for all sorts of outcomes, where the abilities of the characters
If not anything else, this should at least make players avoid Charisma as a dump stat...