어야지 어떡하다

what else can you do?

States the only remaining option and then throws up its hands: 그렇게 해야지 어떡하겠어요, 'that's what you have to do, what else is there?'. The 어떡해/어떡하겠어 part is rhetorical — no answer is expected. It is used to accept something with a shrug, sometimes cheerfully, as in 이제 좋아해야지 어떡해, 'well, she has no choice but to like it now'. The ending scales from blunt 어떡해 to polite 어떡하겠습니까.

Register: casual to polite, resigned