、。
Ambition is worth having, but it isn't easily achieved.
Literal
Ambition [topic-は] hold-[worth-に値する]-[but-が], easily not-achievable-[passive potential-され得ない].
Literary/formal sentence. ~に値する ('be worth doing') is a formal way to express worth — more elevated than ~に価する. 抱く ('hold, embrace') is the verb for embracing feelings, ambitions, and dreams. 達成され得ない uses the classical potential ~得る ('be able to') combined with the passive, giving 'cannot be achieved.' Very written register.