저를 전적으로 믿으셔야 합니다

Origin

"You must trust me completely" comes from the way Kim Ju-young (Kim Seo-hyung), the college-admissions coordinator in the JTBC drama SKY Castle, handled the mothers who hired her. The series aired from November 23rd, 2018 to February 1st, 2019 and peaked at 23.7% for its twentieth and final episode (AGB Nielsen nationwide), a record for Korean non-terrestrial television at the time.

Strictly speaking, the sentence never appears in that exact form. Whenever Han Seo-jin (Yum Jung-ah) panicked about her daughter Ye-seo's grades, Kim Ju-young would flatly reply, "Mother, you must trust me." The word "completely" migrated over from a different line — "leave Ye-seo's grades entirely to me" — and the two fused in public memory. It is a textbook case of a famous quote that the audience assembled.

Spread

Over the two months in which the drama climbed from 1.7% to the low twenties, the phrase became a catchphrase. On January 11th, 2019, Ajunews wrote that the line had "gone past being dialogue and become a catchphrase spawning parodies"; on the 29th, a Herald Business column ran it as a headline while discussing the growth of rolling admissions and the fairness debate around comprehensive school records. The catchphrase had crossed into education discourse.

Parodies almost always copy the delivery: low, slow, eyes locked on the listener, and utterly certain without offering any evidence. YouTubers and comedians produced a steady run of impressions, and Kim Seo-hyung herself acknowledged the trend on social media.