Question: When Frollo, has Ezmeralda, in his grip in the the church, he says "I was just imagining a rope around that beautiful neck" and she says "i know what you were imagining", what was he thinking? I assume its something sexual, but its a cartoon.
Answer: The entire point is that he lusts after her. However, the Disney movie does not dive into that nearly as much as the novel.
Answer: It was most certainly sexual. Frollo's whole arc was his fight against his carnal desires (seeing Esmerelda dancing in the fire, sniffing her hair, etc). In order to maintain a G-rating, they couldn't be overtly sexual, which is why it's done through suggestion and subtext.
JC Fernandez