The adjective credible means believable, worthy, or trustworthy. Creditable means worthy of praise or credit and credulous means easily fooled--tending to trust or believe too readily. (Incredulous means skeptical.)

Link to present incidents:
Examples: „Speakers who make eye contact for more than half their speech are viewed as more credible and trustworthy." „They finished a creditable fourth place in the competition.“
„Man is a credulous animal, and must believe something; in the absence of good grounds for belief, he will be satisfied with bad ones" (Bertrand Russell).
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