Core Pattern Rule: -기 마련이다
This pattern is used to express that something is a natural, inevitable, or expected outcome. It's equivalent to saying "is bound to...", "it's natural that...", or "it's a given that...".
Meaning & Usage
Meaning: It signifies that a certain action or state is a universal truth or a natural consequence of a situation.
When to use: Use it when stating general observations about life, human nature, or the world. It often carries a slightly philosophical or reflective tone.
Formation
Simply attach -기 마련이다 to the stem of any verb or adjective, regardless of whether it ends in a vowel or a consonant.
Verbs:
오다 (to come) → 오기 마련이다
잊다 (to forget) → 잊기 마련이다
Adjectives:
아프다 (to be painful) → 아프기 마련이다
어렵다 (to be difficult) → 어렵기 마련이다
사람은 변하기 마련이야. / 꽃은 시들기 마련이야. / 처음은 어렵기 마련이에요. / 비밀은 드러나기 마련이야.
Synonyms & Differences: vs. -는 법이다
The pattern -는 법이다 is a very close synonym to -기 마련이다. Both express that something is a natural rule or tendency. In many cases, they are interchangeable.
Key Nuance
-기 마련이다: Often emphasizes a natural, almost fated process or an inevitable outcome. It speaks to the inherent nature of things. (e.g., Flowers are bound to wither).
-는 법이다: Can feel more like stating a general principle, a rule of thumb, or simply "how things work." (e.g., That's just the way it is).
Interchangeable Examples
사람은 변하기 마련이다. (People are bound to change.)
사람은 변하는 법이다. (It's the nature of people to change.)
서두르면 실수하기 마련이다. (If you rush, you're bound to make mistakes.)
서두르면 실수하는 법이다. (It's a rule that if you rush, you make mistakes.)
For most conversational purposes, you can consider them very similar.
시간이 지나면 잊혀지기 마련이야. / 누구나 늙기 마련이야. / 물가는 오르기 마련이야.