You are going to roleplay with someone without their consent. Without their consent or knowledge. Because they don't know they're part of your game, you don't get a pass on the fiction you're going to present. You will lie, and to that person, you will be a liar. They may never find out, and the interaction might still be a net win for them, but it will be true that you were not. You can be anyone you choose—other than yourself—provided that the thought to choose them does not occur to you before your interaction begins. Everything you say, your character believes implicitly. They're not some filthy liar. There are two ways to win: The conversation ends with your target better off and unsuspecting. Your mark calls you on your bullshit; you apologize and tell them about roleplaying. All other results are a loss. Afterward, think about the value of truth, and how you tried to help your victim. Is it better to lie to help someone, or to say nothing? How did lying-for-real feel? Was your emotional cost worth their gain? What did you learn about your victim? Do you believe that? What of your character will you keep?
Thanks for running this!