How do you spell i won't him in spanish?

I want him = Lo quiero (informal); Le quiero (formal).

"I won't him" is not a complete thought. "won't" is a contraction of "will not" and needs a verb to complete the sentence, i.e. "I won't eat him" or "I won't see him" or "I won't know of him", etc. In Spanish this thought can be partially expressed by "Yo no lo [future verb stem]é." where [future verb stem] should be replaced with the future verb stem of the requisite verb, i.e. "yo no lo comeré" or "yo no lo veré" or "yo no lo sabré" etc. respectively.