To earn the "DOUBTS" trophy in Detroit: Become Human, you must allow the Traci androids to escape at the end of the chapter "THE EDEN CLUB".
Enter the club and investigate the two bodies. When you eventually interrogate the android on the floor you'll learn of a second android in the room. Outside, interact with the android opposite the door and then speak with Hank. Get him to pay for the android. Scan it to start a bloodhound trail; you observe where the android appears to have gone and then scan an android in its field of view. On Casual you have a decent time frame to achieve this so just keep scanning androids vaguely in the path of the escaping android and eventually you'll be led into a staff area. Locate the blue blood on the floor near the pallets on the left and follow it to the back. Look at the line of androids at the back wall to start a quick-time event fight sequence.
You can win this fight (which will help towards another trophy) and still allow the Tracis to escape; in fact doing so will also keep you in Hank's good books for yet another trophy. Just make sure to complete all the QTEs promptly and when you get to the option to shoot or spare the deviant, make sure to spare them. After the scene you'll finish the chapter, and the trophy will unlock during the flowchart.