1. She let (it) slip that she's still in love with her ex husband.2. I am sorry your secret slipped out when I was talking to your wife.3. He blurted out the hiding place of the suspect.
 let (it) slip slip out blurt out這些用法都指不小心說出某些事情，也就是說溜嘴的意思
His family seems happy and united, but it's all a chaade.