an earnest self-criticism
認真的自我批評

carry out the policy conscientiously
認真執行政策

serious self-critical examination
認真的檢討

deal seriously with; take...seriously
認真對待

ponder deeply
認真思考

put a firm check on
認真制止

earnest and serious
嚴肅認真

Be conscientious and make a good job of publishing.
認真作好出版工作。

I was only joking, but he took it to heart.
我是說著玩兒的，他就認真了。