Individual psychotherapy - that is engaging a distressed fellow human in a disciplined conversation and human relationship - requires that the therapist have the proper temperament and philosophy of life for such work. By that I mean that the therapist must be patient modest and a perceptive listener rather than a talker and advice-giver.
Doubt is an uneasy and dissatisfied state from which we struggle to free ourselves and pass into the state of belief while the latter is a calm and satisfactory state which we do not wish to avoid or to change to a belief in anything else.