이라는 건

as for …

→ 이다
phrase Common #3,114
as for … Used after a noun to introduce or comment on what that thing is or means; 건 is a contraction of 것은.
KO: 행복이라는 건 사람마다 달라요.
EN: As for happiness, it’s different for everyone.

사랑 이라는 건 분명히…

Love is definitely…

— 순응자 (1971)