The Collaborative International Dictionary of English v.0.48:
Promising \Prom"is*ing\, a. Making a promise or promises; affording hope or assurance; as, promising person; a promising day. -- Prom"is*ing*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
promisingly adv 1: in an auspicious manner; "the afternoon had begun so promisingly"