My guy, watch the Batman TAS. That's not who she is as a character
She wants a perfect family but with the Joker and in the world he's created. Her dreaming about everything being totally normal implies she really doesn't wanna be Harley which makes zero sense. Even if that was the case, Harley fell in love and descended into madness with and over the Joker, the crazy weird psychotic killer. Why would she dream about being in love with someone who's not that??
I'm not saying it didn't fit her character, the lines were just forced in at awkward parts of scenes or were just timed badly. She made the "pussies" joke once already, and you don't do it twice without changing up the gag, that's a comedy no-no, yet that's exactly what happened in the movie. And not only that, but she just delivers it out of nowhere and its just bad. But I don't put the blame on Margot Robbie for stuff like that because something like that is on the director to change during shooting or the editors to adjust on the cutting room floor