Connie thought that the visitor was Jim because Jim said her that he would come in Christmas and the day when the author went to her was also the day of Christmas. So Connie thought that the author is her husband Jim MacPherson

Connie referred the author as Jim because:

1. Establishing a Personal Connection:
Connie referred to the author as Jim to establish a personal connection and create a friendly atmosphere. By using a first name, she intends to show that she values their relationship and wants to communicate on a more informal and personal level.

2. Sharing a Common Experience:
Connie and the author have been exchanging letters for a year, sharing their thoughts and experiences. By calling the author Jim, she is acknowledging their ongoing correspondence and the familiarity they have developed over time.

3. Signifying Trust and Comfort:
Referring to the author as Jim indicates a level of trust and comfort between Connie and the author. It suggests that they have built a rapport, allowing Connie to address the author in a more familiar manner.

4. Emotional Connection:
The author has shared a poignant story about the Christmas Truce during World War I, which has deeply affected Connie. By calling the author Jim, she expresses her emotional connection to the story and the impact it has had on her. It shows her appreciation for the author's writing and their ability to evoke strong emotions.

5. Reflecting Informal Communication:
Using the author's first name reflects the informal nature of their communication. Since they have been exchanging personal letters, it is likely that their correspondence has been more casual and less formal. By addressing the author as Jim, Connie maintains the same tone and style of their previous letters.

Conclusion:
Connie's decision to refer to the author as Jim is a way of establishing a personal connection, sharing a common experience, signifying trust and comfort, expressing an emotional connection, and reflecting the informal nature of their correspondence. It adds a personal touch to their communication and enhances the bond between them.