Koi no Otemae, Choudai Itashimasu.

Nanako enters high school looking for an afterschool activity and a romantic interest. She thought she'd found both in Yukiya-senpai of the Tea Ceremony Club, but the cool and handsome Yukiya rejected her club application. Nanako wasn't about to give up, though, and Yukiya finally allowed her one week to prove herself worthy of the Tea Ceremony Club. A sweet love story for two over tea!

(Source: Kodansha, translated)