Kural - 709

The eye speaks out the hate or friendly soul of man;
To those who know the eye's swift varying moods to scan

Explanation
If a king gets ministers who can read the movements of the eye, the eyes (of foreign kings) will (themselves) reveal (to him) their hatred or friendship.

Tamil Transliteration
Pakaimaiyum Kenmaiyum Kannuraikkum Kannin
Vakaimai Unarvaarp Perin.