YOU SAID:

She was never supposed to smile.

INTO JAPANESE

彼女は決して微笑むはずがなかった。

BACK INTO ENGLISH

She could never have smiled.

INTO JAPANESE

彼女は決して微笑むことができなかったでしょう。

BACK INTO ENGLISH

She would never have been able to smile.

INTO JAPANESE

彼女は決して微笑むことができなかっただろう。

BACK INTO ENGLISH

She would never have been able to smile.