In anime, sometimes a character's eyes change into hearts. The term for this in Japanese would be haato me ハート目, "heart eyes," but other phrases can be used to describe it, like me ga haato 目がハート, "the eyes are hearts," or me ni haato 目にハート, "hearts in eyes."
This includes heart-shaped pupils and irises, too. Some related words are haato maaku ハートマーク, "heart mark," i.e. ❤, and haato-gata ハート型, "heart-shaped."
Anime: Dumbbell Nan Kilo Moteru? ダンベル何キロ持てる？ (Episode 1)