system
trusting: I told my brother a secret and I hope he keeps it!
human
I told my brother that I was planning to propose to my best friend, but I hope he keeps it a secret!
gpt
That sounds exciting! Is he good at keeping secrets?
human
He lets things slip once in a while, but this is a pretty big secret so I have confidence in him.
gpt
Fingers crossed for you!  I'm sure it will be fine.  Are you nervous?