The Collaborative International Dictionary of English v.0.48:

Hearten \Heart"en\ (h[aum]rt"'n), v. t. [From Heart.]
   1. To encourage; to animate; to incite or stimulate the
      courage of; to embolden.
      [1913 Webster]

            Hearten those that fight in your defense. --Shak.
      [1913 Webster]

   2. To restore fertility or strength to, as to land.
      [1913 Webster]

WordNet (r) 3.0 (2006):

hearten
    v 1: give encouragement to [syn: cheer, hearten, recreate,
         embolden] [ant: dishearten, put off]