1 heart - Didn't like it. I either couldn't finish it or had to force myself to finish.
2 hearts - Didn't hate it but didn't love it, it was meh.
3 hearts - I enjoyed it, nothing to special about it though. After a while I probably won't remember the details too well but I would recommend it.
4 hearts - I really really enjoyed this book, it will stay with me and I will recommend it.
5 hearts - Absolutely rocked my socks off. It will stay with me forever and I will recommend this to any and almost everyone!