undoubtedly
Critics will doubtlessly compare this book to The Year of Magical Thinking by Joan Didion.
The complexity of this excellent series has doubtlessly contributed to its low audience ratings.
They were doubtlessly convinced that their cause was just.
You’re doubtlessly aware that excessive debt is a problem for a significant percentage of our population.
Doubtlessly, some people will feel uncomfortable with this idea.

SMART Vocabulary: related words and phrases

Certainty
(as) clear as dayidiom
(as) sure as eggs is eggsidiom
and that's flat!idiom
assure someone of something
assured
decidedly
deffo
definite
definitely
definitive
ironclad
irrefutable
irrefutably
make no mistake (about it)idiom
mistake
unreserved
unreservedly
watertight
would
you can bet your lifeidiom