What you need to know before deciding to read it: - 
 1) Prefer to read it as continuation of the series. It takes some plot elements from the first book. 
 2) The heroine's back-story involves having been raped and tortured in captivity. None of it has been graphically described but if you're still queasy about it, don't go for it. 
 3) There are some really nasty people in the book, who want to make the heroine's life a hell for no rhyme or reason. They make you want to bitch-slap them so hard, it'll make your palms itch with the need. 
 4) The book does make you emotional at times. But none of it is dragged like a Nicholas Sparks novel, so you'll be okay there.