-기 마련이다 means "bound to" or "its natural that" - expressing inevitability.
Natural outcome - 노력하면 성공하기 마련이에요 (if you try, youre bound to succeed)
Universal truth - Thats just how things are
Inevitable - Cannot be otherwise
See examples below for varied real-world usage.
Expresses natural law or principle
Often with universal statements
With time, youre bound to forget.
Everyone is bound to make mistakes.
It is natural that results come if you put in the effort.
Spring is bound to come when winter passes.
Find real examples
Discover this pattern in manga, dramas & more
Save for spaced repetition
Add sentences to your study deck
Practice -기 마련이다 and other grammar patterns with manga, dramas, and more.
Start learning free