Joy making a decision [Suru] vs. Joy receiving a notice [Naru]
“I decided to go to Japan.” vs “It was decided that I go to Japan.”
In Japanese, we distinguish between decisions you make and decisions made for you. We use 〜ことにする (Koto ni suru) and 〜ことになる (Koto ni naru). Let’s master the difference!
🗣 Conversation Scene
Joy is talking to Ken about her summer plans and work.
(Ken, I decided to go to Japan next month!)
(That’s great! Actually, it has been decided that I will transfer to Osaka, too.)
💡 Explanation
Both phrases connect to the Dictionary Form or Nai-Form of verbs.
Point 1: Koto ni suru (〜ことにする) = My Decision
Use this when YOU decide to do something. It expresses your volition (will).
- タバコを 辞（や）める ことにしました。
(I decided to quit smoking.) - 今日（きょう）は 家（いえ）に いる ことにします。
(I decide to stay home today.)
Point 2: Koto ni naru (〜ことになる) = Result / External Factor
Use this when things are decided by others, fate, or rules. Even if you agreed to it, the nuance is “it turned out this way.”
- 来年（らいねん）、結婚（けっこん）する ことになりました。
(It has been decided that we will get married. [Reporting the fact]) - 明日（あした）は 雨（あめ）なので、中止（ちゅうし）になる ことになりました。
(It was decided to cancel because of rain.)
📊 Comparison / Common Mistake
🚧 Joy’s Mistake
❌ Wrong: 会社（かいしゃ）のルールで、制服（せいふく）を 着（き）る ことにします。
(If it is a company rule, YOU didn’t decide it.)
✅ Right: 会社（かいしゃ）のルールで、制服（せいふく）を 着（き）る ことになっています。
(It is a rule/It has been decided that we wear uniforms.)
🔥 Practice Quiz
Tap to check the answer!
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