Decision to not speak on confidential matters
I'm looking for a word:
I discussed certain confidential matters with my client. She relied on my __ in not speaking of them.
There's a word specifically for this situation, better than "restraint" and essentially opposite to "openness".
Discretion is probably what you are looking for here (meaning 2, or meaning 1 here).
You could use discretion here:
discretion
: the quality of having or showing discernment or good judgment : the quality of being discreet
- She relied on my confidence in not speaking of them.
- She relied on my discretion in not speaking of them.