Kural - 91

Pleasant words are words with all pervading love that burn;
Words from his guileless mouth who can the very truth discern

Explanation
Sweet words are those which imbued with love and free from deceit flow from the mouth of the virtuous.

Tamil Transliteration
Insolaal Eeram Alaiip Patiruilavaam
Semporul Kantaarvaaich Chol.