One great 'A Sign of Affection Fanfic' is 'The Unspoken Feelings'. It beautifully explores the relationship between the main characters in a very heart - warming way. The author does an amazing job of delving into their emotions and the little details of their interactions.
I'm not sure specifically as there could be many novels with this title or related concept. It might be about different ways people show affection in a fictional story, perhaps romantic love, friendship love or family love shown through the characters' actions and relationships.
Well, 'A Sign of Affection' manga is popular because it combines romance and drama in a way that's both heartwarming and exciting. The way the story unfolds is captivating and the illustrations are amazing.