I am very sorry and this is a special letter from me to you，which I want to make clear.(which引导定语从句)

I want to make it clear that I am very sorry and this is a special letter from me to you.(it作形式宾语)

Dear Hans，

　　In the past few days I have done a lot of hard thinking about what happened last week.

　　I want you to know that everything that I am about to say comes from the bottom of my heart.I know that it will be very difficult for you to accept my apologies，but I want you to think about our friendship as well.The main reason why I decide to write you this letter is that our friendship is so valuable that we can't lose it over a silly argument.I know I should not have been so rude to you.I admit that it was my fault.

　　I want to make it clear that I am very sorry and this is a special letter from me to you，and I hope you can forgive me.

　　I am looking forward to your reply.

Yours truly，

Mary