absolutely
actually
and no mistake
assuredly
at all events
at any rate
by all means
certainly
clearly
decidedly
decisively
definitely
distinctly
factually
for a certainty
for a fact
for certain
for sure
historically
in fact
in reality
in truth
in very sooth
indeed
indeedy
most assuredly
most certainly
nothing else but
of a truth
of course
positively
really
really-truly
surely
to a certainty
truly
undoubtedly
unequivocally
unmistakably
verily
veritably
with truth