I was thinking that the general wants to interrogate the main character, but kidnapping a daughter of the governor is a bit much. Thus the second option is to "buy" her from the father, formally, marry her, and since general's position is high, plus he can threaten the civilian official, plus he can make it profitable for the father, they could strike a quick deal. But there is some etiquette to follow.
Of course, the general does not give a damn about the aunt, cousin etc. But he may want to use some honey to make the girl more cooperative.