The Collaborative International Dictionary of English v.0.48:

Promise \Prom"ise\, v. t. [imp. & p. p. Promised; p. pr. & vb.
   n. Promising.]
   [1913 Webster]
   1. To engage to do, give, make, or to refrain from doing,
      giving, or making, or the like; to covenant; to engage;
      as, to promise a visit; to promise a cessation of
      hostilities; to promise the payment of money. "To promise
      aid." --Shak.
      [1913 Webster]

   2. To afford reason to expect; to cause hope or assurance of;
      as, the clouds promise rain. --Milton.
      [1913 Webster]

   3. To make declaration of or give assurance of, as some
      benefit to be conferred; to pledge or engage to bestow;
      as, the proprietors promised large tracts of land; the
      city promised a reward.
      [1913 Webster]

   Promised land. See Land of promise, under Land.

   To promise one's self.
      (a) To resolve; to determine; to vow.
      (b) To be assured; to have strong confidence.
          [1913 Webster]

                I dare promise myself you will attest the truth
                of all I have advanced.           --Rambler.
          [1913 Webster]

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):

promising
    adj 1: showing possibility of achievement or excellence; "a
           promising young man"
    2: full or promise; "had a bright future in publishing"; "the
       scandal threatened an abrupt end to a promising political
       career"; "a hopeful new singer on Broadway" [syn: bright,
       hopeful, promising]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "promising":
   apt, auspicious, benign, benignant, bright, bright with promise,
   cheering, couleur de rose, encouraging, fair, favorable, favoring,
   foreseeable, fortunate, full of promise, golden, good, happy,
   heartening, hopeful, in the cards, inspiring, inspiriting, liable,
   likely, looking up, lucky, odds-on, of good omen, of happy portent,
   of promise, optimistic, positive, predictable,
   predictable within limits, pregnant of good, presumable,
   presumptive, probable, propitious, prosperous, reassuring,
   rose-colored, roseate, rosy, statistically probable, supportive,
   verisimilar