A: Have you seen her social media?
B: Yes, I have. She said she’d broken up with her boyfriend.
A: Yeah. She posted all kinds of things.
B: I hope she doesn’t regret it later. It’s better to keep something like that private.
In this situation, what should you say ‘keep something like that private’ in Japanese?
Casual
B：そういうことは心にしまっておくほうがいいよね。
Note: This is not a word-for-word translation.
Advanced Tips
According to Google Translate:
B：そういうことは内緒にしておいた方がいいよね。
This is OK, and I think we sometimes say that.
However, when talking about a person themselves, as in this case, 心にしまっておく would be more appropriate.
しまう has two meanings, but here it derives from the first, which means to keep something in one’s heart and not make it public.
- To put something back in its original place or container after use.
- To finish something.
If you want to tell someone to keep something private after sharing a secret with them, it’s better to say 秘密にしておいてね / 内緒にしておいてね or 内密にお願いします / ご内密に.
The latter is rather more formal.
Kotoba no Hibiki 