Spend some time watching movies with confession scenes.
From my friend Deacon Steven Greydanus:
From the earliest days of the silent era, the Church has taken an interest in the world of cinema — and vice versa.
From the Church’s side, iconography and imagery in various forms, liturgical and otherwise, have a perennial place in Christian culture, and the power of images to educate is fundamental to the Catholic imagination.
From the perspective of filmmakers, church buildings, ecclesiastical vestments and the liturgy represented for much of Christian history the most impressive spectacle in most people’s regular experience, and this new form of spectacle took a natural interest in the photogenic trappings of the Catholic tradition.
Of the seven sacraments at the heart of the Church’s life, from the very beginning perhaps the most intriguing to filmmakers has been, ironically, the least visually impressive — a hidden rite involving only the minister and the recipient.
Perhaps the very secrecy surrounding the sacrament of confession was part of what attracted filmmakers to depict it. Anyone can witness the Eucharistic liturgy, an ordination or a wedding, and anyone can be present at the anointing of a sick person, but what transpires in confession can only be imagined — which is the cinema’s stock in trade.
Penance is also, in a sense, the most dramatic (or drama-friendly) sacrament. The personality and struggles of the penitent are exposed, potentially in a unique way, and put into some kind of perspective. The seal of the confessional, too, offers dramatic possibilities that have intrigued writers since the Middle Ages.
Often enough, confession scenes have served in movies as a pretext to allow a character to articulate their spiritual or temporal struggles, whether or not any kind of sin is involved.
Despite the number of movie scenes set in confessionals, a good confession — especially as an occasion of real moral conversion, or as a staple of religious life — is a relatively rare thing on the big screen. Screenwriters have often used confession scenes for character development, for thematic reasons, or for dramatic or comic effect, but seldom as a moral turning point.
From there, he goes into a great overview of confession scenes in movies — some famous, some obscure. Read it all.