true believer

American  

noun

1. a person who has been thoroughly convinced of something.

2. a fanatic, especially a religious or political one.

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Example Sentences

Taub is a true believer in the democratic process, and in the power of a unified populace to effect real and lasting change.

From Los Angeles Times

Milei is a libertarian true believer whose reckless budget-slashing has driven Argentina into a deep economic crisis.

From Salon

Greene, at least, seems to be a true believer in the cause, and she seems to genuinely want the Epstein files released.

From Slate

I went to Texas dubious, but 9,000 calories later, I’m afraid I’ve become a true believer.

From Slate

So while Fuentes may survive longer as a true believer, he’ll never gain as much money and influence as the grifters.

From Salon