고백성사, or the Sacrament of Reconciliation, is a practice in the Catholic Church where individuals confess their sins to a priest. This sacrament is based on the belief that through confession, one can receive forgiveness and restore their relationship with God. During the confession, the penitent expresses remorse for their sins and may receive guidance or penance from the priest. The sacrament emphasizes the importance of repentance and spiritual healing, allowing individuals to experience a sense of renewal and peace in their faith journey.