Miwa is a shy girl who cannot hide her feelings very well.
She brushes off whenever her best friend Yuuka says "I love you" to her since she thinks Yuuka is teasing her. She and Yuuka have been friends for a long time, and she even is close to Yuuka's mother, running errands for her such as carrying lunch for Yuuka on days the school football team has practice.
Miwa affectionately calls Yuuka "Yuu-chan" though she is extremely unaware of her best friend's love for her and especially does not realise how much pain she is causing her when she asks Yuuka to deliver her love letter to the object of her affections, Misumi.

Related manga:

Kawaii Anata Manga, 2007
Love Letter Manga, 2008