Anne writes a letter during the story. Explain what is the purpose of that letter?

Anne writes a letter during the story. Anne wrote to her mother during the holidays. Mother was in Canada and she had a special love for the narrator’s daughter Marian. Anne wrote down to vent out her feelings and also because her mother was deeply concerned about Marian. Anne’s mother always wanted to hear about improvements in Marian and usually flipped through pages to find where Anne mentioned about Marian. She often thought that Anne should start the letter with Marian’s mention and then go on to other things. On the other hand, Anne was a widow and Marian on her age and due to her inabilities was not capable of talking or understanding what went on within Anne. So the letter was a way to let out her emotions on a piece of paper.