Dear Li Hua，
My purpose in writing this letter is to express my sincere apologies to you. Maybe you don't know yet, but I have to apologize to you first. The detailed thing is this.
Here's the thing. Remember the day before yesterday when you asked me to bring you a magazine from Xinhua bookstore? I remembered it when I went to school today, and I was going to buy you one by the way. When I walked into the bookstore, I was sad to see my favorite book, so I decided to read a book I liked first. Sure enough, as I expected, the book I liked was released in a new color. So I bought it without hesitation. When I paid to step out of the store, I remembered that I needed to bring you a magazine. I remember it very well. So I went to the store and asked the manager if there was anything new in that magazine you were talking about? He replied that there was, so he asked me to look for it myself. I went to the shelf and found a book he thought of, right there. In order to ensure that this is the new version, I specifically asked the store manager if it was a new issue. He also replied that I said yes, so I bought it. But what I never imagined was that when I got home, I and my classmates, after a little communication, he said that this is not new. So I'll just have to give it to you the day after tomorrow. I'll buy you the exact same one, but it may be a little late. I hope you'll understand.
If you can forgive me, I will be very grateful and look forward to your early reply.