Aloof Female Professor, the Brother's Sister? I Make My Move and Win Her Over

[No System + One Heroine + Older Woman-Younger Man Romance + Business]

From the start, he is a college student who happens to meet an online girlfriend while surfing the internet.

After days of anticipation and torment, she finally agrees to meet him.

But on the day they meet, his mysterious girlfriend turns out to be his roommate's older sister, and even his academic advisor. Just as he's thinking of making a run for it,

who could have guessed that his buddy's sister would drag him off to register their marriage?

“Isn't this a little too fast? I'm not ready yet!”