よろこんじゃう
yorokonja u

Godan Verb (u)
Godan Verb (bu)

The completive aspect (contracted form) - indicates completion or regret of 喜ぶ

1. To be pleased/happy (with a nuance of unexpectedness or self-reproach); To be delighted (with a nuance of unexpectedness or self-reproach)

Completed Action
Colloquial