“认真的”的英语可以翻译为：demure，douce，earnest，serious，serious-minded ...

在他看来，这个人无疑是认真的。There was no doubt in his mind that the man was serious.你是认真的呢，还是有点胡闹？Were you serious, or was that a bit of tomfoolery?你准是在开玩笑。你是认真的吗？You're joking. Are you serious?...