He said just that a couple years ago (she's a terrific Sec of State and I like her) and she will use it in TV ads, you can bet.
I can see it now. The ad opens with the announcer blasting "Trump endorses Hillary Clinton!" And it appears in big, red, white, and blue letters on the screen. Then, in old-fashioned newsreel style, the show stumpy saying nice things about hitlery. And then, hitlery, in the prevent day and age, at a rally, saying, "Thank you, thank you, Mr. Trump, for your endorsement."
All interspersed with clips of stumpy saying liberal, progressive things.
With a tagine of, "Why vote for the echo?"