This is earned by follwing the "Truthful ending"
This is the true ending of the game and can only be completed in NG+ (The game marks this as a "completed" save file).
To do this, you first need to save Ryo.
Making sure to prioritise Ryo and Shuuji between chapters 1-4. Once Ryo hits 50+ affinity, he'll survive the game.
If these two survive, I've never seen anyone else death scenes of Ryo is alive. So, I'm certain that saving him means everyone will survive regardless.
The choice in Chapter 8 doesn't seem to matter too much as you'll always get the ending for this trophy.