He has entered the serene autumn of his life.

他已进入了美好的中年时期。

She has a lovely serene face.

她有一张可爱而安详的脸。

It is thus that, athwart the cloud which formed about him, when all his hopes were extinguished one after the other, M.Mabeuf remained rather puerilely, but profoundly serene.

马白夫先生便是这样，他在处境日益黯淡、希望一一消失的情况下心境却仍然宁静如初，这虽然带点稚气，但很固执。