Rob: It’s on a neutral territory, there is also innocence to it -
Seamus: Of course, it’s like two kids talking about their feelings.
Rob: The purspose of the scene (…) which is, you know, “I wanna be your girl, I wanna be your girfriend, I wanna be that special person. And I will as soon as I get this thing out of the way because I can’t commit for both”; and it gives Castle, you know, a reason to hung in there. But there is no doubt that he has been very patient with her struggles, but it’s just a testament of how much he loves her, which I think it’s…incredibly cool.
(Rob Bowman, Jon Huertas, Seamus Dever, and Tamala Jones episode commentary - about the swingset scene)