She's completely honest.
她很誠實。
I'd like you to give me an honest answer/your honest opinion.
我希望你給我一個誠實的回答/坦誠的意見。
He had an honest face (= he looked like he could be trusted).
他看起來忠厚可信。
To be honest (with you), I don't think it will be possible.
(跟你)說老實話,我認為那根本不可能。