German phrase
Bitte vertraulich behandeln.
Meaning
Please keep confidential
When to use it
It requests confidentiality. This polite wording suits formal business settings.
Example dialogue
Hier sind die Unterlagen. Bitte vertraulich behandeln.
Here are the documents. Please keep them confidential.
Natürlich, ich behandle die Unterlagen vertraulich.
Of course, I will keep the documents confidential.