give someone the benefit of the doubt
US /ɡɪv ˈsʌm.wʌn ðə ˈben.ə.fɪt əv ðə daʊt/
UK /ɡɪv ˈsʌm.wʌn ðə ˈben.ə.fɪt əv ðə daʊt/

1.
to believe someone's statement, even if you have doubts, because you have no proof that they are lying
:
•
I'll give him the benefit of the doubt and assume he's telling the truth.
•
Despite the rumors, we decided to give her the benefit of the doubt.