A smile and a heartfelt "Thank you".
The most appropriate reply would be "Thank you."
When someone says "thank you" to you, you should reply by saying : "You're welcome"
Whatever you said to him to make him feel flattered does not need a reply or, you could say 'You are welcome.'
One normally does not have to reply to a thank you letter.
You can reply to "How do you do?" by saying "I'm well, thank you. How about you?" This is a polite way to acknowledge the greeting and show interest in the other person.
"Thank you" and a sincere complement in return is usually acceptable.
if you mean in french , when it means thank you, then i would type "no problem" or "its okay" into a word translator on the internetMerci in French is "thank you" "De rien" is one reply that means you are welcome or you can use "pas de quoi".
my pleasure
good, thank you and you? best reply when someone says Comment allez-vous? maybe :d
response
you welcome