Dear Bob, I'm writing the letter to inform you that I wish to express my sincere apology to you.
To begin with, I take this opportunity to extend my heartfelt appreciation to the kind assistance you render me during my stay in Canada.
What's more, I borrowed one CD of Beethoven's symphonies from you in Canada.
Unfortunately, when I returned home, I found to my surprise that CD in my personal baggage due to my carelessness.
To solve the problem, I would like to send this CD to you by Express Mail Service. Once again, please accept my sincere apology for any inconveniences that I have caused.
I hope the settlement of the matter will meet your wishes.
Yours sincerely, Li Ming