To earn the "CONFESSION" trophy in Detroit: Become Human, you must get a confession out of the android in "THE INTERROGATION". Of course you're not going to be able to do that if you didn't catch the android in the first place, so you won't be able to get this trophy if you didn't already earn the one below (see my guide there for instructions):
You should also ensure that you located the statue in the bathroom during "PARTNERS" and looked at RA9 scrawled on the shower wall - this gives you the most comprehensive options when probing the suspect and gives you more options later in the game.
In the interrogation you want to get the android's stress level up into the rectangular area of his stress bar, above 50 and below 75 (on Casual difficulty), and keep it there until you're done with the questions.
Here's a safe strategy:
Whatever happens at the end of the chapter, as long as you got the confession you will get the trophy when you reach the flowchart.
A couple of notes on how the end of this chapter can affect other trophies and how you might want to adjust your approach accordingly: