He was reacting to her tweeting that if he got elected, she'd move to Canada, so under the circumstances he wasn't being mean. Not too mean, anyway. And he was notably non-sexist. He said "actor" (not "actress," not that I think "actress" is bad) and he said "mojo" (a term for "sex appeal" or prowess in general that, if anything, skews male).
And I'm sure I've made this point before, but why does anyone think leaving the country is a strong statement of opposition to a particular President? Only you are leaving the country. The country is stuck with this President you think is so terrible. Isn't your objection to what this person will do to the country as opposed to you personally? What is accomplished by your departure? It seems to me that you're only serving your own interest in escape from what you don't like to experience, but the experience of someone being the President is, for most of us, only reading and hearing about it, and the news will still reach you in Canada. It's just so self-involved and self-coddling and upper-middle-class entitled, but perhaps that's the character she plays on Twitter and it's supposed to sound lame and confused, like the character she plays on "Girls."
Trump's joking continued: "Now I have to get elected because I'll be doing a great service to our country. Now it's much more important. In fact, I'll immediately get off this call and start campaigning right now." Now, now, now.