"She finally smiled."

Translation: 她终于笑了！

[yession]

For those learning Chinese, just want to point out that the Chinese character 笑 can mean both "smile" and "laugh". To differentiate, if you want to say "smile", usually 微笑 is used. But here if you replace 笑 with微笑, it sounds odd. More natural way to say "she finally smiled" in Chinese is 她终于露出了微笑, which literally means "she finally revealed a/her smile"