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

🇯🇵妹の友達が何考えてるのかわからない · Imouto no Tomodachi ga Nani Kangaeteru no ka Wakaranai

MangaFinished🇯🇵 First published in 2020ComedyRomanceSlice of Life

Rei Okiumi story, art

Chie's big brother finds himself dumbfounded and perplexed by his younger sister's 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.

Synopsis via AniList