Dear Mary,
I am writing to you to express my apology.I am sorry for what I said to you yesterday afternoon.It was rude.I did not mean it.I was angry and out of my mind at the moment I said those to you.I realised afterward that I was wrong and you must have been hurt.I am sorry,Please forgive me.
I want to make it up to you.Please let me know what I can do for you.I want to see your smile again,please.
Sincerely yours,
xxxxxxx