Text of Mindy's letter, in case you can't read it:

Dear Jonathan,
I really am sorry to put you through this, but I can't take it anymore. I'm sure I died peacefully--please don't mourn for me.
Jonathan, I still love you. I know you don't need me anymore, now that you have Anna, and I understand. I guess I haven't been able to let you go. I put the ring I was going to give you in the letter. You can have it if you want, or pawn it. I couldn't bear to return it.
Please don't blame yourself for this. I have my own problems. Don't let Anna think it's her fault, either.
It's better this way--maybe I'll finally be at peace.