Thanks @may71
She kept saying our relationship is OVER
As I said we were so close to each other. But now, I don't know what is the right choice (sending letter or not). On one hand, I hope I could post this letter to her. On the other hand, I'm scared to know the result, she might return my letter or throw it away. Or if her husband got this letter, probably he will throw it away directly without informing her
Maybe you could send her an email?
I was a terrible Goddaughter. Anxiety disorder is not an excuse to get her forgiveness, also is not an excuse to forgive myself.
There's every reason for you to be forgiven, and for you to forgive yourself.
Do you want to say more about why her husband doesn't want you to see her?