in all conscience

actively earnestly passionately sincerely vigorously

gravely

all joking aside cool it cut the comedy determinedly down fervently for real in all seriousness in earnest intently purposefully resolutely sedately simmer down soberly solemnly sternly straighten out thoughtfully with a straight face with forethought with sobriety zealously

casually funnily lightly minor trivially

candidly deeply earnestly genuinely naturally profoundly really truly truthfully wholeheartedly

aboveboard frankly from bottom of heart in all sincerity in good faith ingenuously without equivocation

doubtfully

dishonestly untruthfully