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Both "existe" and "existirá" are forms of "existir", which is often translated as "to exist". Learn more about "existir" below.
existir()
An intransitive verb is one that does not require a direct object (e.g., The man sneezed.).
1. (to be real)
a. to exist
Mi hermanito todavía cree que existe el Coco.My little brother still believes the Boogeyman exists.