give (someone or something) the benefit of the doubt
To retain a favorable or at least neutral opinion of someone or something until the full information about the subject is available. You're my sister! Can't you give me the benefit of the doubt, instead of believing the worst about me right away? Let's give him the benefit of the doubt before we start accusing him. There may be a good explanation for the missing money.
give somebody the ˌbenefit of the ˈdoubt
accept that a person is right or innocent because you cannot prove that they are not: She said she was late because of the traffic and I gave her the benefit of the doubt.