joking apart/aside

said when you want to start speaking seriously about something after making jokes and laughing about it

言归正传，说正经的

Joking apart, will you be able to manage on your own?

言归正传，你自己能应付得了吗?

I know I laugh at him but, joking aside, he's a very clever scientist.

我知道我经常嘲笑他，但说正经的，他是一个非常聪明的科学家。