naïve

her naïve enthusiasm was infectious and brightened the room.

he had a naïve belief that everyone was inherently good.

the naïve approach to security left them vulnerable to attack.

it was naïve of her to trust him after what he'd done.

his naïve questions revealed a lack of understanding of the situation.

don't be naïve; the world isn't always fair.

she was a naïve young woman, easily taken advantage of.

the naïve assumption that success comes easily is often wrong.

he displayed a naïve optimism despite the grim circumstances.

it's naïve to think you can change the world on your own.

her naïve comments often embarrassed her colleagues.