misbelieve
/ˌmɪsbɪˈliːv/verb
1 [with object] To believe falsely or suppose erroneously that something is the case. Now rare.
2 [with object] Not to believe; to distrust (a person); to disbelieve (a thing).
Origin
Middle English. From mis- + believe, probably after Anglo-Norman and Old French mescreire, mescrere.