The riot ended after police negotiated with the group and convinced them coming out.

英訳に間違いが有れば正してください。

暴動は警察がグループと交渉し、説得して彼らを出てこさせて終わった。
The riot ended after police negotiated with the group and convinced them coming out.

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答え comingをto comeにする

The riot ended after police negotiated with the group and convinced them to come out.

comvince+目的語+to V
説得して目的語にVさせる