Final answer:
Without the context of the letter and details regarding Margaret's conversation with Barow, it is not possible to determine Margaret's opinion of him or any bias she may have.
Step-by-step explanation:
The student's question relates to understanding the opinion of Margaret towards Barow based on her conversation with him in a letter. Margaret's opinion of Barow is not directly mentioned in the provided text, thus making it impossible to draw accurate conclusions without additional context. Furthermore, without specific textual evidence, discussing Margaret's potential bias against Barow would be speculative. It is essential in literary analysis to have direct references from the text to support any interpretation of a character's opinions and biases.