The Collaborative International Dictionary of English v.0.48:

gladsomeness \glad"some*ness\ n.
   The state of experiencing joy and pleasure.

   Syn: gladness, gladfulness.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Gladsome \Glad"some\, a.
   1. Pleased; joyful; cheerful.
      [1913 Webster]

   2. Causing joy, pleasure, or cheerfulness; having the
      appearance of gayety; pleasing.
      [1913 Webster]

            Of opening heaven they sung, and gladsome day.
                                                  --Prior.
      -- Glad"some*ly, adv. -- Glad"some*ness, n.
      [1913 Webster]

            Hours of perfect gladsomeness.        --Wordsworth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gladsomeness
    n 1: experiencing joy and pleasure [syn: gladness,
         gladfulness, gladsomeness]