Opponents may have different Stats depending on which action you choose. That is, that they will be better at defending against some types of actions over others. In most cases, the stats you will see in the Opponents' card will be a guide/indication only. It can be worth clicking through each action to see what your chances of success are with each type of Action, using different Sworn Swords in your Keep.
The duration of the quest is variable, but it can be accelerated by using Food.
Since the Build Release dated 23 July 2013, most Sworn Sword Quest seem to take in excess of three hours, some take in excess of seven.