공든 탑이 무너지랴 · 공든 탑이 무너지겠어요?
sincere hard work never goes to waste (lit. would a tower built with great care collapse?)
Example
공든 탑이 무너지랴, 그동안 열심히 준비했으니까 좋은 결과가 있을 거예요.
Hard work never goes to waste; you've prepared so hard, so you'll get a good result.
Word parts
공 merit, effort+탑 tower
공든 is 공(功) 'effort' + 든 'that has gone into' (from 들다): a tower built with real care won't fall down. -랴 is an old rhetorical question ending.
Good to know
Used to reassure someone waiting for results. In news, 공든 탑이 무너지다 is used for years of effort being ruined in an instant.