The story
- Old English · inherited fromġelēaffulnes“faith, trust, faithfulness”
- Middle English · inherited from*bileffulnesse
- English todaybelieffulness
From Middle English *bileffulnesse, from Old English ġelēaffulnes (“faith, trust, faithfulness”), equivalent to beliefful + -ness.
Etymology from Wiktionary, CC BY-SA 4.0.