Yuna (ユウナ), the younger sister in Oujo no Meirei de Stalker to Kekkon Saserareru Hanashi (王女の命令でストーカーと結婚させられる話) by Nigiri Usagi. Her glasses change during the manga but it seems to default to the square glasses and can also do round glasses. I've assumed brown hair and green eyes, like the one panel of her sister Reina that has been colored on the artist's twitter.
Prompt
yunanigiri,short hair,round glasses,green eyes,brunette hair,small breasts