French phrase
Je dois y réfléchir ~.
Meaning
I need to think about it ___.
When to use it
It says that time is needed to consider something. It is polite and cautious when postponing a reply.
Example dialogue
Je dois y réfléchir avant de répondre.
I need to think about it before I reply.
D'accord, tenez-moi informé.
All right, please keep me informed.