The Collaborative International Dictionary of English v.0.48:

disenchanting \disenchanting\ adj.
   freeing from illusion, credulity, overoptimism, or false
   belief.

   Syn: disillusioning.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Disenchant \Dis`en*chant"\, v. t. [imp. & p. p. Disenchanted;
   p. pr. & vb. n. Disenchanting.] [Pref. dis- + enchant: cf.
   F. d['e]senchanter.]
   1. To free from enchantment; to deliver from the power of
      charms or spells.
      [1913 Webster]

            Haste to thy work; a noble stroke or two
            Ends all the charms, and disenchants the grove.
                                                  --Dryden.
      [1913 Webster]

   2. to free (a person) from fascination or delusion; to
      destroy the false hopes or overoptimistic expectations of
      (a person); to disillusion; -- used with people or events
      as the agent (subject); as, the candidate was disenchanted
      by the low turnout at the rally.
      [PJC]

WordNet (r) 3.0 (2006):

disenchanting
    adj 1: freeing from illusion or false belief [syn:
           disenchanting, disillusioning]