Well there's many reasons that she left him in charge. Only one of which was to show the Forsaken that he was worthy. The more often they had to follow him, the more they would see that he deserved to be crowned. And with hey being named Warchief, it was something she was intending to come to pass. The Forsaken needed a separate representation within the Horde. Yes, that representation would be highly bias, being her husband, but Vergil could be trusted to question her if it was warranted.

"Flatterer." Ah, but she smiles. One of her real smiles, that only he and Nero can bring to her. The kind of smile that made the onlookers talk behind their hands, because the rumors are true. Warchief Sylvanas really was smitten with her half demon husband.

"Are you in the middle of anything pressing?"