It seems to be that the story I am recalling was taught in a high school or college English class. The premise was that a girl of unknown lineage falls in love with a man from the south of the United States (possibly mid 19th century). They proceed to almost get married, but somehow it becomes known that she may have a drop of African blood in her lineage, and he denies her. The twist at the end is that it turns out that he is in fact of mixed lineage. Yet she became shunned, and I can’t remember but I think she may have committed suicide at the end of this story.
Anyway, help would be greatly appreciated and rewarded with good karma.