never fail to

释义：非常经典的一个双重否定表达。“一定会”，常在留学文书里形容某门学科对自己的吸引力，不过用来自夸似乎又过了一些。

例句：
Her naturally husky voice never failed to captivate him.
You never fail to uphold your end and contribute to the good of all.