The quality or state of being full of belief, faith, or strong conviction.
From beliefful + -ness (suffix creating abstract nouns). Combines belief with the fullness concept and then nominalizes it to describe the overall state of being conviction-filled.
Languages love to stack suffixes like building blocks—'belief' becomes 'beliefful' (adjective) then 'belieffulness' (noun)—showing how English lets us zoom in on the essence of any quality!
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