நல்ல மாட்டுக்கு ஒரு சூடு, நல்ல மனிதனுக்கு ஒரு வார்த்தை
Nalla maattukku oru soodu, nalla manidhanukku oru vaarthai
Meaning
A good ox needs branding only once; a good person needs telling only once - the wise don't need to be told twice.
Story
A teacher pointed out a single mistake to one student. While the other students repeated the same mistake again and again, that one student never did. "One word was enough for him," the teacher said with quiet satisfaction.
Reader's Note
Taking a correction to heart the first time is its own kind of strength.