Who is she?

I have a friend, a good friend, but she doesn't know we're friends, i speak to her everyday and i tell to her all my secrets, fears, good and bad things about my life but she never listen to me, I type letters to her, but she never recive them. I have a good friend, but i don't know her name and i don't know where she lives or what she does... i just know she's my friend, my good friend.