I've once given it to a friend without telling him what it was exactly and he sure did sleep through it, he said he didn't feel anything at all and he was up from the night before (was in vacation). Asked him how he felt afterward and he reported no issues sleeping a couple of hours after taking it.
We were young and yes, he did trust I wouldn't give him poison. I certainly didn't have a reputation of using illegal drugs, he knew I dabbled with supplements like Piracetam / Ashwagandha etc.