When my daughter chose to read East, we did not know it was based on the story collection called East of the Sun, West of the Moon (EOTSWOTM) and we had not read any of the Norwegian fairy tales in that beautiful collection.
We loved East, which describes in great detail, the life of Rose (called Karen in EOTSWOTM), who, like Beauty in Beauty and the Beast, comes to love the beast (in this case a white bear) who forces her to leave her home and loved ones.
If this sounds like what happens to young women who marry "A man shall leave his mother and a woman leave her home...", well, it is a fairy tale, and many do believe that fairy tales serve didactic purposes. And, as in the Norwegian tale, in East also, the abducted girl is required to allow the bear, unasked, to sleep next to her each night. When the girl cannot bring herself to do this, and instead lets her mother know of the conditions of her confinement with the beast, she puts in jeopardy the life of the beast and her future happiness.
At least, in East, unlike in the fairy tale, this particular girl is a special one, a person of great initiative and many talents. Her ability to weave, to teach, to learn languages and survival skills, and to endear herself to others, human and other-worldly, and her love of adventure, make it possible for Rose to save her family, herself, and her true love.
East mostly overcomes its origins in a tale in which subordination of women by men and the tearing of the bond between mother and daughter is implied to be necessary to the success of a marriage. It is one of those stories that we loved reading, although we did not necessarily buy its underlying message in its entirety.