Kural - 621

Smile, with patient, hopeful heart, in troublous hour;
Meet and so vanquish grief; nothing hath equal power

Explanation
If troubles come, laugh; there is nothing like that, to press upon and drive away sorrow.

Tamil Transliteration
Itukkan Varungaal Nakuka Adhanai
Atuththoorvadhu Aqdhoppa Thil.