I Don't Understand What My Sister's Friend Is Thinking

Synopsis

Chie's big brother finds himself dumbfounded and perplexed by his younger sister's best friend, Tsuyu, as she doesn't say much. She seems to space out often and blushes easily, but what on Earth is going on in her head? Though she's quiet and shy, Tsuyu seems to have romantic goals of her own as this coming-of-age story unfolds. Follow along with this young trio as they learn about each other in this cute tale of love and growth. (Source: Mangamo)

Anime adaptations