Everything about the title is atmosphere. Sunset, tides, the heart: three images stacked one on top of another, and the promise is mood before plot. Lena Whitford offers Sunset Tides of the Heart on our romance shelf, and it does not pretend to be anything more complicated than what the cover says.
The length is the interesting part. At two and a half hours this is a novella rather than a novel, a form romance has always used well, going back to the days when a story of that size was something you finished in one sitting by the fire. It asks for an afternoon, not a fortnight.