re=re+lent, imagine you lent something to your friend, and you need it back but your friend needs it even more than you do, so you relent and lend the thing again.
u lend, he gives back. u lend again. he becomes less serious this time
relate it with relax means to calm down so when anything calm down it become less severe......
I resented that relentless asshole who didnt lend me some money