All truths are not to be told

सत्यं ब्रूयात् प्रियं ब्रूयात्
न ब्रूयात् सत्यमप्रियम् ।
प्रियं च नानृतं ब्रूयात्
एष धर्मस्सनातनः ॥

One should speak pleasant truth. One should not (directly) say truth if it is harsh, neither should one cook up pleasing words that are not true. This is an eternal principle.

All truths are not to be told.