take someone's word for it
US /teɪk ˈsʌm.wʌnz wɜrd fɔr ɪt/
UK /teɪk ˈsʌm.wʌnz wɜrd fɔr ɪt/
1.
to believe that what someone says is true, without checking or proving it
:
•
I haven't seen the report, but I'll take your word for it that it's accurate.
•
He said he finished all his homework, and I had to take his word for it.