It'll be a  cakewalk.
→   아주쉬울꺼야.

[예문]
A:Oh, Come on, you're going to do just fine.
  자, 괜찮아, 넌잘할수있을꺼야.

B:Everyone keeps telling me that,but I'm still afraid I might screw up.
  모두들 그렇게 말하지만 일을 망칠까봐 걱정이야.

A:It'll be a  cakewalk. Don't worry!
 아주 쉬울꺼야.걱정마.