It says וישכב אתה ויענה, which may in fact be an idiom for rape, but it might also conceivably not. Literally it's simply, "he lay with her and he afflicted her."
Now, I personally tend to think that it probably is idiomatic for rape, if for no other reasons than it is consistent with the story, and that I think it stretches the bounds of pshat interpretation to suppose that the two terms are not linked as part of the same unit of meaning, since generally speaking the phrasing indicates a causal progression.
But while I may think that the pshat is definitely rape, there is no reason whatsoever that one might not make a midrash that tells the story differently, by playing with the meanings of those words. Classic midrashim have often played with language in far more radical ways than this would take.
And since any midrash the text will bear is potentially a valid reading of the text, there is ample room for Jay's drash above.
As I noted, the text says וישכב אתה ויענה, and the phrasing is a typical construction indicating a causal progression or a pair of ideas linked in parallelism. Also, the typical expressing of consensual sex in the Tanach is וישכב עמה, where the word עמה indicates "with her," implying "together with her," or "along with her;" but this says וישכב אתה, which is quite different. The use of אתה is directional, indicating something done to someone, rather that something done with someone. And, in case that were not clear enough, the action is followed with ויענה, which is "afflicted her" or "tormented her," or "humiliated her," but in any case is clearly something to do with causing pain. This is either a parallelism, with the ויענה reflecting and amplifying the sense of וישכב אתה, or it is causally linked-- וישכב אתה, which resulted in ויענה.
Plus, there's the greater context: if he didn't rape her, and the ya'anuha refers to some other kind of pain not associated directly with the sex, why is it that Shimon and Levi-- clearly quick to anger and not given to holding back on their responses-- take vengeance on Shechem for "treating their sister like a whore," rather than taking out their rage on Dinah for running away to be with some man their family disapproves of (not that I would condone such a response on their part, only that it would be a typical and common response to such a situation from the culture of that time and place-- after all, think of Yehudah's first reaction when he finds out that Tamar is pregnant). They clearly feel that it is Dinah who has been wronged, and not Dinah who has done wrong-- and this is a time and place where men were pretty quick to blame women for things and to violently repress any rebellious sexuality women displayed. Nor, in confronting Shimon and Levi, does Yakov protest that it was Dinah who did wrong by running away: he merely expresses anger and anxiety that the decimation of Shechem was politically imprudent.
Like I said to Mike, I think you can absolutely make a midrash that Dinah wasn't raped, and/or that her relations with Shechem were consensual, and that midrash, as a midrash, would be a valid reading of the text. But I don't think you can make a very convincing argument for the pshat of the story to be that she wasn't raped.
