Optimist (noun)

A person who tends to expect the best possible outcome or dwell on the most hopeful aspects of a situation.

Origin:

From latin optimus ("best"), from opto ("i choose, i wis.h")

Examples:

1. He is an optimist and always sees the glass half full.
2. Despite the difficult situation, he remained an optimist.
3. She is an optimist and always looks for the silver lining.
4. He is an optimist and always believes that everything will work out for the best.
5. The optimist in her hoped that the situation would soon improve.