kunRanaiya kuRRam seyinum guNam koLLum
inRu mudhalAga en nenjchE! - enRum
puRan uraiyE Ayinum ponnAzhik kaiyAn
thiRan uraiyE sindhiththiru 

Meaning:

en nenjchE 			- O my mind!
inRu mudhalAga  		- From this day forward
enRum  				- forever
puRan uraiyE Ayinum  		- even if only said outwardly
sindhiththu iru  		- keep in mind
pon Azhik kaiyAn thiRan uraiyE	- only that which pertains to the Lord with the beautiful Sudarshana chakra;
kunRu anaiya kuRRam seyyinum	- (then) even if sins committed are like a mountain
guNam koLLum  			- without thinking of those, He will consider only the good.

Vyakhyana Saram:
Azhvar's divine heart feared that even though He has the nature of destroying the enemies of the devotees, could we who have committed countless sins approach Him. So Azhvar is telling his heart "Do not fear. If you simply show an interest in Him, He will consider even your sins as good only."