Ao Haru Ride
Ao Haru Ride (or Blue Spring Ride) is a romance manga by Io Sakisaka and ran from February 2011 to February 2015. An anime adaptation ran in 2014, and a live action film was also released. In junior high school, Futaba Yoshioka was ostracized by the other girls because of her popularity with boys. The one boy she liked, Kou Tanaka, also moved away. Now in high school, she changed her image to fit in better. However, she meets Kou again, who now has the name Kou Mabuchi and a cold attitude.
Page.12 (Volume 4, Chapter 12)
One of Futaba's acts while putting off asking Kou a serious question is drinking seven glasses of water.
Anime version of Chapter 12.