betray

verb

1. reveal unintentionally"Her smile betrayed her true feelings"
2. deliver to an enemy by treachery"Judas sold Jesus"
3. disappoint, prove undependable to; abandon, forsake"His sense of smell failed him this time"
4. be sexually unfaithful to one's partner in marriage"She cheats on her husband"
5. give away information about somebody"He told on his classmate who had cheated on the exam"
6. cause someone to believe an untruth"The insurance company deceived me when they told me they were covering my house"