prick (someone's) bubble

Translations
разрушить (чьи-то) иллюзии
When Jane told him the truth about his business idea, she pricked his bubble.
Когда Джейн рассказала ему правду о его бизнес-идее, она разрушила его иллюзии.
Definitions
To ruin someone's illusions, excitement, or sense of self-importance by revealing an unpleasant truth or reality; to deflate someone's enthusiasm or confidence.