できる：dekiru：can / be able to~ はず：hazu：it must be/do~ / so, できるはず means (someone must be able to do ~ ) ＥＸ： 私は、彼はこの問題が解決できるはずだと思う。 I feel he must be able to solve this problem. I am sure he can solve the problem.

dekiruhazu = must be able to