I wouldn't call this a *dirty* trick, per se
Well, this was really cute. You knew it was going to be a problem when Trick came up with his plan, but he kinda had it right that Grace wouldn't see him in any romantic light if some chicanery wasn't involved. And I pretty much see her point based on how he was when she met him. But a boy in love's gotta do what a boy in love's gotta do, right? And considering all the bad things people can do to each other, this one doesn't really rank anywhere near the lowest of the low. Everything he did was done with good intentions. And I can understand, with Grace's history, why it was such a problem for her, but I was glad with how it all turned out.