Millie pouted slightly, not the practiced pout of a more elegant woman but a teasing expression she didn't really put in that sort of context. She might look different, and be different in many ways, but she was still in large part the same girl as before, only more grown up. "Awww," she said, attempting to wheedle but knowing he wouldn't give in to her.
She didn't hesitate more than the general half-second almost anyone would hesitate after the war before agreeing to let him transport her. She trusted Draco, as much as she trusted anyone. He wouldn't mean her any harm--that she knew for certain.
Her lips parted in a little 'oh' of surprise at the charmed gazebo and the lovely intimate setting. "You did this for me?" she asked, almost awestruck. It had taken him some time to put together, and it flattered her that he would go to so much trouble--for her.
In another scenario, perhaps she would have worried that he didn't want anyone to know about her--but this was Draco, and he too was different than they'd been in school. This kind of planning showed caring, and so she didn't even give it half a second of thought. "It's wonderful," she told him, leaning in to give him a reassuring kiss of appreciation.