Honor system

Good morning friends,

Trying to express the concept of "honor system" to my lawyer this morning and wondering what the closest equivalent would be? The context is that we are selling a piece of real estate and leaving the furniture in for a few days after closing. I want to ask my lawyer if we are going to protect ourselves with a contract on the furniture or trust them "honor system" that they will give us the furniture when they finish with it?

Thank you.

Cosmas

Normally you would say something like Θα αρκεστούμε σε προφορική διαβεβαίωση or στον λόγο (της τιμής) τους, but for legalese you'll have to wait for an expert's opinion (maybe προφορική συμφωνία?)