Helen Hoang's The Heart Principle follows Anna Sun, a violinist whose viral cover earned millions of views but left her paralyzed by performance anxiety. When her long-term boyfriend suggests opening their relationship, Anna embarks on a series of one-night stands, seeking to prove she can be the spontaneous, adventurous person he wants. Instead, she meets Quan Diep, a tattooed motorcyclist whose patience and acceptance begin to heal wounds Anna barely knew she carried. Hoang, who has been open about her own autism diagnosis, writes Anna as a character on the spectrum, portraying the sensory overwhelm of performances, the exhaustion of masking, and the relief of being accepted as oneself. The novel deals with serious themes including burnout, family expectations in Asian American households, and grief over a parent's illness, yet maintains the warmth and hope characteristic of romance. Hoang's portrayal of Quan is equally nuanced; his tattoos cover scars from cancer treatment, and his gentleness reflects hard-won self-knowledge. The Heart Principle is the third book in Hoang's Kiss Quotient series, but stands alone. Readers will find both an emotionally satisfying romance and a sensitive portrayal of neurodivergence. Hoang demonstrates that love stories can address mental health and disability without sacrificing joy or passion.