Melania Trump said Marco Rubio's campaign has taken a "desperate tone" toward Donald Trump, but the Republican front-runner's wife is unbothered.

Rubio finally engaged Donald Trump at last Thursday's Republican debate and hasn't let up since, aggressively branding the billionaire as a "con man," calling out his business ventures and attacking his "small hands" and alleged spray tan.

Asked about the Florida senator's intensifying rhetoric, Melania Trump told CNN's Anderson Cooper in an interview broadcast Tuesday that she expected it.