The story is about love potion, a conversation between a seller and a customer:
"How carefully she will look after you! She will never allow you to be tired, to sit in a draught, to neglect your food. If you are an hour late, she will be terrified. She will think you are killed, or that some siren has caught you."
"I can hardly imagine Diana like that!" cried Alan, overwhelmed with joy.
What is "to imagine Diana like that!" in the text above? Thanks..