Kural - 514

Even when tests of every kind are multiplied,
Full many a man proves otherwise, by action tried

Explanation
Even when (a king) has tried them in every possible way, there are many men who change, from the nature of the works (in which they may be employed).

Tamil Transliteration
Enaivakaiyaan Theriyak Kannum Vinaivakaiyaan
Veraakum Maandhar Palar.