undoubtably

I leave it to all the Protestant Princes of Europe to judge if their safety can be solidly established in their Leagues and Confederations with the Princes of the Roman Communion, as it may be undoubtably effected by their Leagues and Confederations amongst themselves.

1679, Edmund Everard, Discourses on the present state of the Protestant princes of Europe, London: Dorman Newman, page 20

Maugham suggests that storytelling began when primeval hunters told tales around their fires and turbaned raconteurs held forth in what Sinclair Lewis called the clattering bright bazaars. He's undoubtably right.

1963 October 5, Charles Poore, “Books of The Times: The Curtain Speeches of Somerset Maugham”, in New York Times, page 18

Thus, by analogy, philosophical propositions will involve primitive terms, to be arrived at, undoubtably, by a kind of conceptual analysis.

2003, M. Van Atten, J. Kennedy, “On the Philosophical Development of Kurt Gödel”, in The Bulletin of Symbolic Logic, volume 9, number 4, page 431