Plain Jane: A Novel of Jane Seymour by Laurien Gardner is rather self-explanatory as far as subject matter is concerned. When I was researching the image of the book cover (which is an actual portrait of Henry, Jane and Eward, c.1545) I discovered no less than five books titled "Plain Jane".
So, if you want to read about the one wife Henry VIII might have actually loved (inasmuch as he was capable of that particular emotion), make sure you pick up the historical fiction novel by Laurien Gardner. Jane Seymour shares Henry's tomb at Windsor Castle, which might be a testament to the validity of Henry's affection.
The above portrait of Jane Seymour was painted by Hans Holbein the Younger, a painter often commissioned by Henry.
Plain Jane is told in Jane's voice and commences when she is 9 years old. Doomed to spinsterhood because of her lack of beauty, her destiny changes when she is appointed Anne Boleyn's maid of honor and Henry's ever-wandering eye falls upon her.
As a footnote, Laurien Gardner is the nom de plume of historical/fantasy author, Julianne Ardian Lee,