A Court of Thorns and Roses (A Court of Thorns and Roses #1) by Sarah J. Maas
Sarah J. Maas may no longer be the reigning queen of Romantasy, but don’t count her out yet. She’s slipped down the bestseller list recently, but clearly, there are still a ton of people just discovering her books — and once they finish this one, there are many more thousands of pages to go in Maas’s fantasy series. This book currently has 2.5 million ratings on Goodreads, with a 4.2 average rating.
(Technically, this is in the #6 spot, but I’ve lumped #4 and #5 together for obvious reasons.)