From Lezhin:
Eun Sian, otherwise known as Shanshan by her good friend Hyunee, is popular with all the girls at school. Which would be great if she swung that way, but she doesn’t. It just happens that she’s terrified of men, and her mother is obsessed with protecting her from all men. And suddenly, Yuri, the prettiest girl at school, has admitted to Sian that she has feelings for her. Now Yuri won’t stop following Sian around, which would also be fine by Sian, except it seems like Yuri wants Sian all to herself... and who knows how fall she’ll go to make sure that happens.

Original Webtoon
Official English Translation
Official Japanese Translation