Definition
To say that someone will never hear the end of something means that the person will repeatedly talk about it, either proudly or disapprovingly.
永无宁日，永远听他/她喃囉不停（形容很喜欢显摊或批评人的样子）
If he wins the competition, you will never hear the end of it.
如果他赢得比赛，你将会一直听到这件事。
I'm sure I'll never hear the end of it from her once she knows I made a mistake.
我确定一旦她知道我犯了错，我将会一直听到这件事。
Once he starts talking about his new car, you'll absolutely never hear the end of it.
一旦他开始谈论他的新车，你绝对会一直听到这件事。