Answer:
"Dear *librarians name*
I understand what I did was wrong. I failed to turn in *book name* which many other kids could've used. It was selfish of me, and next time I need to do the right thing. I hope you can forgive me, and it will never happen again.
I am so sorry, from *your name*
Step-by-step explanation:
This is a pretty funny situation, ive been there. Make sure you change whats written in * and remove the quotation marks!