How to Say ‘I’ll be good.’ in Japanese
いい子にする。
ii ko ni suru
[ee koh nee soo-roo]
💬 Usage Tip: [いい子にする。] means “I’ll be good” or “I’ll behave.” It sounds like a promise, often from a child.
🇯🇵 In Japan: This can sound cute and childlike. Adults may use it jokingly for humor or to sound playful.
Phrase Breakdown
いい子
ii ko
good child; well-behaved child
A phrase meaning someone is well-behaved or acts nicely.
今日はいい子だったね。
You were a good child today.
Words in this phrase
いい
ii
[ee]
good
いい means “good.” In this phrase, it describes 子, meaning a good or well-behaved child.
いい子にする。
Make (someone) a good child / decide to be good.
子
ko
[koh]
child
子 means “child.” Combined with いい, it means “good child.”
あの子をいい子にする。
Make that child into a good child.
にする
ni suru
make into; behave as; act like
The verb する used with いい子 to mean 'be good' or 'behave well.'
いい子にするよ。
I’ll behave well.
Words in this phrase
に
ni
[nee]
into; as
に marks the target state. It shows what something will become.
むすこをいい子にする。
Make my son into a good child.
する
suru
[soo-roo]
to do; to make
する means “to do” or “to make.” In this phrase, it means making someone or something into that state.
この子をいい子にする。
Make this child into a good child.
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