喜ぶ, 悦ぶ, 歓ぶ, 慶ぶ, よろこぶ
Conjugated: 喜んでいた
Godan verb, Transitive, Intransitive
1. to be delighted, to be glad, to be pleased, to rejoice
2. to congratulate
3. to welcome (a proposal, advice, etc.), to take kindly to
See 喜んで, as よろこんで...
4. to do with pleasure, to do gladly, to be happy (to do)
喜んであなたのお手伝いをします。