Objective: To examine the pressure on therapists to fake sincerity and the significance of genuine sincerity in psychotherapy. Conclusions: There are many reasons why therapists might fake sincerity. We live in a post-modern culture of dissimulation and ‘playing the game’ that puts a premium on faking sincerity. Manualised and scripted psycho-therapies encourage fake sincerity, as do the measurement requirements of EBM, and the short-term approach of Managed Care. Kohut's ‘corrective emotional experience’ of empathy reinforces benevolent faked sincerity. Studies demonstrate the importance of the therapist appearing warm and genuine but do not differentiate appearance from reality. Therapists may fear that true sincerity will lead to crossing boundaries, harming patients, being poorly judged or medico-legal problems. Nevertheless, if therapists aren't willing to strive for genuine sincerity, despite all the attendant risks and possible complications, then they deny their patients the opportunity of working through the difficulties of achieving sincerity in any human relationship. Moments of true mutual sincerity in psychotherapy are healing not only because of the insight achieved but also because they restore the damaged hope that sincerity is possible. Therapists who fake sincerity ultimately leave their patients feeling alone and colluding in a mutually fake therapeutic relationship.