시작이 반이라고 · 시작이 반이잖아요
getting started is half the battle (lit. the beginning is half)
Example
시작이 반이라고, 일단 헬스장에 등록부터 했어요.
Getting started is half the battle, so for now I've signed up at the gym.
Word parts
시 begin+작 make+반 half
Literally 'the start is half (of the job)': once you begin, you're already halfway there.
Good to know
Used to encourage someone who keeps hesitating, or to praise a first step. Close to the English 'well begun is half done'.