The Collaborative International Dictionary
Believing \Be*liev"ing\, a. That believes; having belief. -- Be*liev"ing*ly, adv.
Wiktionary
adv. in a believing manner
WordNet
adv. in a credulous manner; "the children followed the teacher credulously" [syn: credulously] [ant: incredulously, incredulously]
Usage examples of "believingly".
God then concluded all those in unbelief, both Jews and Gentiles, whom He foreknew and predestinated to be comformed to the image of His Son, in order that they might be confounded by the bitterness of unbelief, and might repent and believingly turn to the sweetness of God’s mercy, and might take up that exclamation of the psalm, "How great is the abundance of Thy sweetness, O Lord, which Thou hast hidden for them that fear Thee, but hast perfected to them that hope," not in themselves, but "in Thee.
But suddenly my introductory note which I'd included so open mindedly, but not believingly, loomed as a real possibility, and more than that, I guess I stopped believing.