This occurs on T&T Chapter 3 and Part 3: Investigation.
This chapter is where you meet Violetta in Tender Lender halfway through the current investigation.
A Psyche-Lock will trigger when you mention about her head bandage.
NOTE: Before presenting the Magatama, I advise you save your current progress, as this trophy requires you to deliberately get a question wrong and you will lose a marginal health bar.
Otherwise, just present the Magatama straight away and deliberately present the wrong evidence, she'll mention her home-made donuts and you'll unlock the trophy as of then.