credibly

adverb2

1. •
   In a credible manner; believably.

   • A suitor can credibly signal his love for a woman by offering her an expensive and extravagant gift.
   • He was in a position to commit to a credibly conservative monetary policy.
2. •
   Used to report the speaker's assessment of the credibility of a reported statement

   • He [Mayor Koch] says he better understands the limits of government; less credibly, he says he has mellowed. — 1989