(I) can't say for sure

(I) can't say for sure

I don't know with certainty. A: "How many people are coming to dinner tonight?" B: "I can't say for sure—my family tends to just show up without responding to invitations."
See also: say, sure
Farlex Dictionary of Idioms.

(I) can't say for sure.

Inf. I do not know with any certainty. Tom: When will the next train come through? Jane: I can't say for sure. Bob: How can the driver hit so many potholes? Bill: Can't say for sure. I know he doesn't see too well, though.
See also: say, sure
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • can't say for sure
  • can't rightly say
  • (I) can't rightly say
  • rightly
  • for sure
  • for certain
  • (I) can't say as I do(, can't say as I don't)
  • (I) can't say as I do
  • can't say as I do
  • (I) can't say's I do