To evaluate the events in "Engaged to the Nun" translated by Herbert A. Giles, the most useful piece of context would be understanding the official or unwritten rules of betrothal in this culture. This context will provide insight into the societal norms surrounding engagements and marriages, including the role of parents, particularly mothers, in choosing spouses for their children.
Understanding these rules can illuminate the motivations and intentions behind the characters' actions, shedding light on the societal pressures and traditions that may influence their decisions. It will also help in interpreting the dynamics of the relationships presented in the excerpt and how they align with or challenge those cultural norms.
While knowing how weddings were typically celebrated or the duration of typical engagements can also provide useful context, the rules of betrothal are fundamental in directly addressing the social constructs at play in the characters' engagements and choices.