You will get this trophy if you can convince the robber to leave Hassan's shop.
Go on your way to the left 'cause you will make noise if you go the middle way or the way to your right.
After sneaking up the robber will detect you and you have to choose the following conversation options:
- Drop Weapon
After that the robber should leave. The trophy will unlock at the next loading screen!
Gus and Geoff from Achievement Hunter made a video guide to watch the steps. All credits for the video go to them.