indubitably
adverb /ɪnˈdjuːbɪtəbli/
  /ɪnˈduːbɪtəbli/
(formal)- in a way that cannot be doubted; without question synonym undoubtedly- He was, indubitably, the most suitable candidate.
 Word Originlate Middle English: from Latin indubitabilis, from in- ‘not’ + dubitabilis (see dubitable) + -ly.