"I'll be sure to make you smile again, to make you whole again…" あなた　or name を きっとまた笑（わら）わせて、幸(しあわ)せにします(:polite)/幸せにするよ(:casual)。 I wasn't very sure the meaning of the latter part of the sentence. If "to make you whole again" means something like to make you happy, that should be 幸せにします. If it means to make you heal wounds, that should be 傷を癒してあげます(きずを　いやしてあげます)／傷を癒してあげるよ（きずを　いやしてあげるよ）. I hope this helps!