For beginners, I'd suggest 'City of Bones'. It has a clear plot and the characters are well - developed. The love story is a major part of the book and it's easy to follow. 'The Vampire Diaries' is also suitable. It's a well - known series that has a lot of appeal. The romance aspect is quite strong and the supernatural elements are not overly complicated. 'Shadow and Bone' is a good option too. It has a unique magic system but it's not too difficult to understand, and the love story adds an extra layer of interest.
Well, 'Twilight' could be a good starting point. It's very popular and has a straightforward love story set in a fantasy world. The characters are easy to relate to. 'Outlander' might also work, although it has some complex elements like time - travel. But the love story is so central and well - written that it can draw in new readers. And 'The Darkest Minds' is another one. It has an interesting post - apocalyptic setting and a love story that is not too hard to follow for those new to the genre.