不入虎穴，焉得虎子
Nothing venture, nothing have(gain).
No pains, no gain.

eg：Go and ask your boss to give you a promotion.
Nothing venture , nothing have.

中英俚语俗语来源：后汉书·班超传：“班超使西域，谓其官属曰，不入虎穴，不得虎子。”