The Collaborative International Dictionary
Gladdening
Gladden \Glad"den\, v. t. [imp. & p. p. Gladdened; p. pr. & vb. n. Gladdening.] [See Glad, v. t.] To make glad; to cheer; to please; to gratify; to rejoice; to exhilarate.
A secret pleasure gladdened all that saw him.
--Addison.
Wiktionary
gladdening
vb. (present participle of gladden English)