Don't take it seriously. he's only joking.

　　他是在說笑話兒，別當真。

　　He's only joking; don't take him seriously.

　　他這是玩笑，你別認真。

　　I was only joking. Why take it so seriously?

　　開個玩笑嘛，何必當真呢？

　　Don't take her too seriously; she's only flirting with you.

　　別把她太當真，她只不過是在和你調(diào)情罷了。