fretfully
Regretfully Yours was created in 1996.
regretfully, i walked away from my one chance to be a star.
Apologetically or remorsefully.
Yes it is.
REGRETFULLY is the correct spelling.
McCandless regretfully calls the discovery of his father's affair one of the greatest tragedies of his life.
Regretfully. Filled with regret.
Regretfully, no.
The correct spelling of the adverb is apologetically (in apology, regretfully, remorsefully).
It looks clumsy and overdone. Simply use regret.
Regretfully, it has value only of a utilitarian nature.
'We regretfully advise you...' or 'We regret to advise you...' would be correct versions of your example.