The pop band Backstreet Boys has this song Quit Playing Games (With My Heart). I wonder what idiom can describe the phrase "play games with someone's heart"? Apparently the phrase "playing games with the heart" sounds perfectly good, but I wonder if there is any other phrase to convey the same meaning. Googling the phrase, it seems that there is no dictionary acknowledgement of it. The closest idiom could I get is play one's heart out, but it's about being enthusiastic and devoted when playing something (sports, game, instrument).
The idiom should describe the intention to gain someone's confidence, only to betray it.