French phrase
Je ne suis pas sûr de comprendre.
Meaning
I'm not sure I understand.
When to use it
Expresses uncertainty about full understanding. It is politely used to clarify an unclear detail, especially in work-related discussions.
Example dialogue
Je ne suis pas sûr de comprendre. Quelle est la date limite ?
I'm not sure I understand. What is the deadline?
La date limite est vendredi.
The deadline is Friday.