Grace Livingston Hill 
Stranger within the Gates [EPUB ebook] 

Sylvia Garland’s impulsive brother brings home a bride from college, shocking the whole family. The bride doesn’t appear to be a good fit for the family, still Sylvia determines to befriend her. But Florimel is out for her young husband’s inheritance, pitting mother and son against each other and throwing the Garland family in so much turmoil that Sylvia may miss her own chance at love.