Dear {Recipient},
I would like to apologize to you for {behavior}. I did not know that {behavior} is considered inappropriate in your culture. In my culture, {behavior} is considered acceptable and is in fact quite common.
Now I know that in your culture, {behavior} means {explanation}.
I am very sorry to have offended you. I have now educated myself further about your culture, and I hope that this incident will not affect our future relationship.
Sincerely,
{Sender}
