An optimistic or hopeful attitude — expecting positive outcomes and looking on the bright side.
彼はいつも楽観的なので、困難でもあまり心配しない。
He's always optimistic, so he doesn't worry much even in difficulties.
楽観的な見通しが外れて、計画を見直す必要が出てきた。
The optimistic projection failed, and we needed to revise the plan.
楽観的な性格の人はリスクを過小評価しがちだ。
Optimistic people tend to underestimate risks.