ingenuous

Her ingenuous smile made everyone in the room feel immediately at ease and welcome.

(Chinese) 她那纯真的微笑让房间里的每一个人立刻感到轻松自在和受到欢迎。

The child asked an ingenuous question about why adults often tell small lies to each other.

(Chinese) 孩子天真地问了一个关于为什么大人经常互相撒小谎的问题。