This is the 4406th most frequent Japanese word.
喜
"喜" means "joy" or "喜" means "to rejoice."
Here, '喜んで' is the verb showing the act of rejoicing or feeling happy, used in its te-form combined with 'います' to indicate a continuous state.
彼の成功を心から喜んでいます。
I wholeheartedly rejoice in his success.
Here, '喜びました' is the past tense of the verb '喜ぶ', indicating that the act of rejoicing or being delighted happened in the past.
彼女の知らせに大いに喜びました。
I was greatly delighted by her news.
Here, '喜び' is used as a noun meaning 'joy' or 'delight', combined with 'を感じなかった' to express not experiencing joy.