wild-eyed optimist

Translations
безумный оптимист
He is a wild-eyed optimist, always believing things will work out.
Он безумный оптимист, всегда верит, что всё получится.
Definitions
A wild-eyed optimist is a person who has an enthusiastic and often unrealistic belief in positive outcomes, characterized by an intense and sometimes irrational hopefulness about the future.
Words
optimist

noun
оптимист
wild-eyed

adjective
безумный