You borrowed something from your friend later it got damaged Write letter to your friend In your letter you should apology about the issue tell how it got damaged say you are going to fix this issue

Dear Reena,
I Hope you are doing well. I am writing to tell the reason I have not return your dress that I borrowed from you. I really apologize for the delay in returning your dress. I am in so guilt that I do not know how to tell you the truth. Finally, I dared for this.

To be honest, I have never thought that this could be happened with me. Although, this has happened unintentionally but I am feeling very bad. I know it is one of your favorite dress and close to your heart as It was gifted by your father.
I wore this dress on my brother’s marriage and everyone loved it a lot. When I was having a coffee there. Someone kicked me in a rush and whole cup of coffee splashed on the dress. I tried to clean it with water immediately but stains of coffee did not remove.

Now I have sent this dress to the dry cleaner for cleaning. They give me assurance that dress will be fine . It will be available to me by next week and then back it to you soon.

I am really sorry for this mishappening. Hope you forgive me.

Best wishes and looking forward hearing from you

Gurjeet kaur