IdiomDaily LifeFrench

Croire dur comme fer

Meaning: To believe something with complete and unshakeable conviction.

Literally: To believe hard as iron

Example: “Mon grand-père croit dur comme fer que la Lune influence ses tomates.” — My grandfather is utterly convinced the moon affects his tomatoes.

Origin: Iron supplies the hardness, and the comparison attaches to the believing rather than to the thing believed. It usually carries a suggestion that the conviction outruns the evidence.

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