"I know who you are," you say. "You're the daughter of Edwin VanCleef, the legendary founder of the Defias. Your legacy hasn't gone unnoticed." Vanessa looks simultaneously flattered and disturbed. After a few seconds, she composes herself and says, "Then you must know what we will ask of you." Vanessa makes another gesture to the guards. Two of them leave, then return with a bound and gagged man wearing a Stormwind tabard. "This man has caused the loss of one of our most valuable members," she says, anger rising in her voice. "He has led to our ruin time and again. He represents the state of Stormwind that oppresses us, and all else that we fight against. If you want to gain our trust...then kill him."
Kill him. Refuse. See if you can make it look like you've killed him without actually taking his life. Bluff your way out of this. Pretend he's someone the Defias doesn't want to kill.