The story revolves around a young woman named Catherine who is deeply in love with a man named Harry. She is known for her beautiful long pigtail, which she cuts off and sends to Harry as a symbol of her love and devotion. This act of self-sacrifice and her unwavering love for Harry are what make her "faithful" in the story.
The pigtail itself is a symbol of Catherine's beauty and femininity, and the act of cutting it off represents her willingness to sacrifice everything for her love. It's a poignant reminder of the lengths to which people will go for love, even if it ultimately leads to heartbreak.
It's important to note that the story has a tragic ending, as Harry ultimately betrays Catherine's love. Therefore, her faithfulness is ultimately unrequited, making the story even more poignant.