Ruka Sarashina is a vibrant and energetic character from the anime series 'Kanojo, Okarishimasu' (Rent-A-Girlfriend). She is introduced as a rental girlfriend who becomes deeply interested in the protagonist, Kazuya Kinoshita, after finding out about his high heart rate during their date, which she interprets as a sign of true love. Ruka is determined and persistent, often going to great lengths to win Kazuya's affection. Her cheerful personality and unwavering dedication add a unique dynamic to the series, making her an essential part of the story.