A real happiness smile, what's known as a Duchenne smile, after a neurophysiologist who studied it, involves moving the eyes.

真正开心的微笑是杜乡式微笑，在一个神经心理学者研究后发现，包括眨眼睛。

耶鲁公开课 - 心理学导论课程节选

your boss asks you to take on a project that you really want to take on and you really enjoy

你的老板让你参与一个你特别想加入的项目，你做得很开心，

That's why 课堂 - SpeakingMax英语口语达人

If it's a true happiness smile, that's actually bodes better for the relationship than a Pan Am, or greeting smile.

如果是一个真正开心的微笑，对这段感情来说是个好兆头,比问候式微笑好的多。

耶鲁公开课 - 心理学导论课程节选