Final answer:
Without specific context from the text it is difficult to determine how a character named Amanda knows about the situation of unmarried women; however, possible sources include personal experience, societal observation, or cultural learning.
Step-by-step explanation:
The question is referring to a character named Amanda from a play or literary piece. To determine how Amanda knows about the plight of unmarried women without further context is challenging, but we can infer that such knowledge often comes from either personal experiences, societal observations, or cultural teachings. Amanda may have observed the treatment of unmarried women in her society, could have discussed it with people like Laura, or may have read about it. Without the specific text, it is difficult to provide a definitive answer.