Dorcas paused for a moment. The Gryffindor had to interpret what he said so that it made sense to her. Basically, he wanted the Hufflepuff to know that she was out of her mind throwing herself at someone who is not interested. Easy enough. Save herself the heartbreak and just hand over the sweater.
Then her eyes widen for a moment, as another thought hit her. A bit wary to ask the question, she stumbled for a moment in her mind with the right words. "You don't want me to pretend to be after you, too, do you?"