Superlative form of certainly: most certainly.(adverb)
Used to indicate emphatic agreement.(interjection)
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Use "most certainly" in a sentence
"The adventurers and evangelists became a familiar cast of favorites, their names coupled like music hall double acts: Burton and Speke, who argued in public about who discovered what; Sam and Florence Baker, who most certainly did not; Henry Stanley, the American self-publicist, and David Livingstone, his Scottish straight man."
"President George W. Bush is most certainly a Matcher, as evidenced by his faith in daily routine and his approach to Iraqi evasions on disarmament."
"Likewise, once those nerves are damaged they cannot be regrown—and most certainly not in an adult."