Sadly

Adverb

 * 1) In a sad manner; sorrowfully.
 * 2) Unfortunately, sad to say.
 * If you think you’re getting out of this place alive, you are sadly mistaken, my friend.
 * Sadly, the two were never to meet again.
 * 1)  Deeply, completely.
 * 2) * 1485, Sir Thomas Malory, Le Morte Darthur, Book VI:
 * and there he founde a bed, and layde hym therein, and felle on slepe sadly.

Thesaurus
abominably, agonizingly, awfully, baldly, balefully, bitterly, blatantly, bleakly, brashly, by ill hap, by ill luck, confoundedly, cruelly, damnably, deadly, deathly, dejectedly, deplorably, despondently, deucedly, dismally, distressfully, distressingly, dolorously, dreadfully, drearily, egregiously, excessively, excruciatingly, exorbitantly, extravagantly, flagrantly, frightfully, funereally, gloomily, gravely, grievously, grimly, harrowingly, heartbreakingly, heavily, hellishly, horribly, improperly, in adverse circumstances, inexcusably, infernally, inordinately, intolerably, lamentably, lugubriously, miserably, morosely, mournfully, nakedly, openly, painfully, pathetically, piteously, pitiably, ruefully, shatteringly, shockingly, solemnly, somberly, sombrously, something awful, something fierce, sorely, staggeringly, terribly, torturously, unashamedly, unbearably, unconscionably, unduly, unfortunately, unhappily, unluckily, unpardonably, unprovidentially, woefully, wretchedly

Etymology
From.