Romance mystery fiction books typically combine two genres in a very interesting way. The mystery part keeps the readers on their toes, making them eager to find out what really happened. The romance aspect adds an emotional depth. Characters may be falling in love while trying to figure out who the killer is or what the big secret is. In 'The Silent Patient', the psychologist is drawn to his patient in a way that is both professional and has a touch of romance, all while he's trying to solve the mystery of her silence.
These books usually have a sense of suspense that comes from the mystery. There could be a murder, a disappearance, or a long - hidden family secret. The romance can be a slow - burn type, where the characters gradually get closer as they work together to solve the mystery. Or it could be a passionate, stormy relationship that is affected by the mystery at hand. For instance, in 'Rebecca', the new Mrs. de Winter's relationship with her husband is constantly evolving as she discovers more about the mystery of his first wife.