While the still picture doesn't show how her gloved, clenched right hand got in the guy's throat, it does show that her right hand is clenched, and her left hand is clutched, grasping the guy's shirt. Neither indicate an effort to keep him away. Were she trying to shove him away or otherwise fend him off, both of her hands would be open.
Grabbing his shirt demonstrates she was trying to keep him close to her and limit his side to side range of motion. Not only is her right hand clenched in a fist, but it's gloved, unlike her left hand. That's indicative of a purpose very different from germophobia when shaking someone's hand. Finally, the man's head has been tilted back from the position it would be in for the action he was performing. That would require a fair amount of force, like a punch to the throat or lower jaw/chin.
As for his punch, it obviously threw her off balance, but neither the pic of her just after she was struck nor in the pic in start of the video is there evidence of cuts, bruises, or swelling. Whether from his skill or her partial avoidance, she was not hurt (other than her pride, momentarily, perhaps).