sure-물론 or 물론이지 why not-왜 안되겠어, 당연히 되지 i think both expressions can be used in similar context.

for most situations, there isn't a good literal translation for this phrase. do you mean as an answer to "let's go get ice cream!"? then you can say 좋아~ or do you mean as an answer to like "can children learn to surf?", then you can use the expressions lohems said.