YOU SAID:

Never tell the truth when a lie will do

INTO JAPANESE

嘘をついた時は決して真実を言わないでください

BACK INTO ENGLISH

When you lie, never tell the truth.

INTO JAPANESE

嘘をついた時は、真実を話さないでください。

BACK INTO ENGLISH

When you lie, don't tell the truth.

INTO JAPANESE

嘘をつく時は真実を言うな

BACK INTO ENGLISH

When you lie, don't tell the truth.