Answer: solemnly

AnswerCrossword Clue
SOLEMNLYWithout cracking a smile
SOLEMNLYWith seriousness
SOLEMNLYCommon way to swear
SOLEMNLYWithout frivolity
SOLEMNLYFormally.
SOLEMNLYWith gravity
SOLEMNLYHow to behave in church
solemnlySOLEMN, serious (thoughtful or subdued in appearance)