1Confession or admission of a crime, wrongdoing, or mistake; acknowledging one's culpability.
犯人は警察に罪を告白した。
The criminal confessed to the police.
彼は盗みの事実をついに告白した。
He finally confessed to the theft.
記者会見で社長が不正の関与を告白した。
At a press conference, the CEO admitted involvement in the misconduct.
2Professing one's romantic feelings to someone; a declaration of love, typically to ask someone out or start a relationship.
彼女に告白したら、付き合うことになった。
When he confessed his feelings to her, they started dating.
バレンタインに告白する予定だ。
I plan to confess my feelings on Valentine's Day.
勇気を出して好きだと告白した。
I gathered my courage and confessed that I liked them.
彼はクラスメートから突然告白されて驚いた。
He was surprised when a classmate suddenly confessed her feelings to him.
3Profession of faith in a religious context (especially Christianity); publicly declaring one's beliefs or creed.
洗礼のときに信仰を告白する儀式が行われた。
A ceremony of professing faith was held at the baptism.
4Confession of sins in a Christian context: admitting one's sins to God or a priest (similar to confession/penitence).
カトリックでは定期的に司祭の前で罪の告白を行う慣習がある。
In Catholicism, there is a custom of regularly confessing one's sins before a priest.