in all seriousness

in all seriousness

In one's sincere opinion; without any disingenuousness. In all seriousness, I think this project plan is severely flawed.
See also: all
Farlex Dictionary of Idioms.

in all ˈseriousness

seriously; not jokingly: Surely you’re not telling me, in all seriousness, that you want to work in a factory for the rest of your life! OPPOSITE: (with) tongue in cheek
See also: all
Farlex Partner Idioms Dictionary
See also:
  • in all truthfulness
  • in all honesty
  • have swallowed a dictionary
  • ain’t 1
  • phased
  • phazed
  • at one's
  • at someone's
  • open one’s kimono
  • gripes one’s butt