" regretfully "

1: with feelings of bitterness or grief;

  * e.g., " ... I must regretfully inform you that you are not among those who have been accepted for our internship program "

•  Synonyms : 

•  agonizingly,

•  bitterly,

•  dolefully,

•  dolorously,

•  grievously,

•  hard,

•  hardly,

•  inconsolably,

•  lugubriously,

•  mournfully,

•  painfully,

•  plaintively,

•  resentfully,

•  ruefully,

•  sadly,

•  sorely,

•  sorrowfully,

•  unhappily,

•  wailfully,

•  woefully,

•  wretchedly

•  Antonyms : 

•  blissfully,

•  gladly,

•  happily,

•  joyfully,

•  joyously