make a believer of
make a believer (out) of (one)
To convince or persuade one to believe or have faith in someone or something. I was really skeptical of his supposed breakthrough, but the demonstration he gave us made a believer of me. Their absolute dominance in the first game of the tournament made believers out of the entire city—now everyone is throwing their support behind the home team!
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
make a believer (out) of someone
to convince someone decisively about something. The game they played made a believer out of me; from now on, I'm betting on them. It was an interesting discussion, but it did not make a believer out of me.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.