Assertion: Therapeutic relationship is a trusting and confiding relationship.

Reasoning: The high level of trust enables the client to unburden herself/himself to the therapist and confide her/his psychological and personal problems to the latter. 

Both Assertion (A) and reasoning (R) are correct and R is the correct explanation of A.

Trust and openness are key aspects of the therapeutic alliance. The high level of trust allows the client to confide in the therapist, sharing their psychological and personal issues. The therapist fosters this trust by being accepting, empathetic, genuine, and warm towards the client. The therapist conveys a non-judgmental attitude and maintains positive regard, even if the client expresses rude behavior or shares aspects that may be considered "wrong." This unconditional positive regard ensures that the therapist maintains a supportive stance towards the client.