I think there is an ulterior motive behind his kindness.

I need more time to understand his temper.

He always keeps his childlike mind and challenges new things.

Please be careful when dealing with him because he has a rough temper.

He always lives without forgetting his child's naive mind.

He couldn't hide his thoughts of love and romance for her.

Her child-like innocent heart is the secret to being loved by people.

His design is always full of playfulness.

Kokoro is my best friend.

His heart was very kind.