The Bubble Love of the Mermaid, Vol. 2 (manga)

Yotsuru Girls’ Academy student Asana Amamizu has always been spurned by her family for her unique physical condition. But her difficult life takes a turn when her past savior and language arts teacher, Sakuya Shigure, ends up as her proposed marriage partner! As the two troubled youths share moments alone, they learn of each other’s secrets and grow closer despite their circumstances. And then, Sakuya makes a certain decision…