Is it ensure, insure, or assure?
late 14c., "action of confessing," originally in religion, from Old French confession (10c.), from Latin confessionem (nominative confessio) "confession, acknowledgement," noun of action from past participle stem of confiteri (see confess). In law, from 1570s. Meaning "that which is confessed" is mid-15c. An Old English word for it was andettung, also scriftspræc.
In some churches, notably the Roman Catholic Church, a sacrament in which repentant sinners individually or as a group privately confess their sins in front of a priest and receive absolution from the guilt of their sins.
In the first few centuries of Christianity, repentant sinners were assigned public penances: sinners had to stay outside the entrance of the church and ask the people going inside to pray for them. The period of public penance could be shortened through an indulgence.
(1) An open profession of faith (Luke 12:8). (2.) An acknowledment of sins to God (Lev. 16:21; Ezra 9:5-15; Dan. 9:3-12), and to a neighbour whom we have wronged (James 5:16; Matt. 18:15).