1
general::
No room for difference of opinion, no alternative, as in We have to agree on the nomination, and no two ways about it. [Early 1800s]
American Heritage Idioms
2
general::
Phrase(s): no two ways about it
no choice about it; no other interpretation of it. (Note the form there’s rather than there are.) • You have to go to the doctor whether you like it or not. There’s no two ways about it. • This letter means you’re in trouble with the tax people. There’s no two ways about it.
McGrawhill's American Idioms And Phrasal Verbs