to trick or set someone up (with a leading question or ploy) to make them reveal the truth or confirm something.
彼の浮気を確かめるために、友達が彼女にカマをかけた。
To confirm his infidelity, a friend set her up with a question.
刑事は容疑者にさりげなくカマをかけて反応を見た。
The detective casually planted a trap in his question and watched the suspect's reaction.
真相を知りたかったから、少しカマをかけてみた。
I wanted to know the truth, so I tried asking a leading question.