"put out of their misery" in Chinese (Simplified)
结束他们的痛苦让他们解脱（引申义）
Definition
意思是结束某人的痛苦，可以是字面上的（比如安乐死动物），也可以是引申义（比如告诉真相或解决令人难受的情形）。
Usage Notes (Chinese (Simplified))
常在非正式或半正式场合使用，原意指让动物脱离痛苦，引申义是帮别人解除心理上的煎熬（比如告诉结果）。总带有解除痛苦的好意。
Examples
The vet decided to put the dog out of its misery.
兽医决定**结束这只狗的痛苦**。
After hours of waiting, someone finally put me out of my misery and told me the results.
等了好几个小时，终于有人**让我解脱**，告诉了我结果。
She wished someone would put her out of her misery during the long exam.
她希望有人能在漫长的考试中**让她解脱**。
If you know the answer, just put me out of my misery already!
你要是知道答案，快**让我解脱**吧！
Watching the struggling fish, he decided the kindest thing to do was to put it out of its misery.
看着挣扎的鱼，他决定最善良的做法是**结束它的痛苦**。
Don't leave me hanging—just put me out of my misery and say what happened!
别吊我的胃口了，快**让我解脱**，说说发生了什么！