It would be sheer madness to trust a man like that.

信任这样的人将是愚蠢至极。

《牛津词典》

It is sheer madness to drive so fast.

开车那么快是极度愚蠢的。

youdao

It would be downright [sheer] madness to do such a thing.

做这种事纯粹是发疯。

《新英汉大辞典》

"Sheer madness, " he says, shivering at the memory.

CNN: Stops and Starts