The Collaborative International Dictionary of English v.0.48:

Embolden \Em*bold"en\, v. t. [imp. & p. p. Emboldened; p. pr.
   & vb. n. Emboldening.]
   To give boldness or courage to; to encourage. --Shak.
   [1913 Webster]

         The self-conceit which emboldened him to undertake this
         dangerous office.                        --Sir W.
                                                  Scott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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