betray (someone's) trust

Translations
предать (чьё-то) доверие
He betrayed her trust by sharing her secret.
Он предал её доверие, рассказав её секрет.
Definitions
To act in a way that is disloyal or unfaithful to someone, causing them to lose confidence in you or feel deceived.
Words
trust

noun
доверие
betray

verb
предавать