take (something) on trust
To believe something implicitly, without requiring that someone provide proof or evidence. I took their explanation on trust, as they've never given me reason before to disbelieve what they've told me. He wants us to take it on trust that he'll pay us back, but he already owes us a substantial amount of money.
take something on trust
to accept that something is true through trust. I don't know if it's so, but I'll take it on trust. CH You will have to take it on trust because I can't prove it.