2: she’s not wrong, that is literally the plot of the episode
3: Having recently re-watched this it strikes me even more that she seems pretty sure he’s gay from the start, especially since literally every female on the show and half the dudes compliment his smoking appearance so there has to be a canon reason why she was thinking of him as “helpful babysitting friend” not “I should really hit that” when the show otherwise portrays everyone as impressed with his face.
4: She totally saw Dean hanging around outside her house at the end of the episode to give Cas a lift into the fan fiction gap.
5: She knows Steve brought his boyfriend to her house while she was out.
6: Considering they cleaned up after a fight/disposed of a body there, the house was presumably suspiciously clean and tidy (and smelled of cleaning products) compared to how she left it.
7: Once she realises no.6 she is going to be forever convinced that Dean and Cas did it on every surface in her kitchen.
In 9×22, Hannah tells Castiel that he must punish Dean because he killed Tessa (well, she killed herself by walking into the first blade). But the angels blame him. So Hannah is like, you must punish him Castiel, or this whole army of angels won’t follow you anymore. And Castiel is unwilling to hurt Dean. So his angel army leaves him.
And shortly after that scene, Metatron is talking to Gadreel about Castiel and says…
(there is a defined pause here…Most people expected him to say Dean)
That’s a funny way to say it. Why not just say he loves humanity? Why say that he is in love with humanity?
Well, if that wasn’t enough, in 9×23 Metatron is talking to Castiel…
This asserts that Castiel’s goal has always been to save Dean. And he will always choose Dean over heaven.
And then when Metatron tells Castiel that Dean is dead:
And shortly after when we cut back to this scene, there are tears in his eyes. Misha actually said he cried in this scene, but it was cut.
I just wanted to add that to my discussion because we never see Castiel cry, but if he ever were to, it would be because of Dean’s death (that’s what I’ve always felt). I think another scene where Misha said he cried as Castiel (and it was cut) was when the angels were falling in 8×23. People have pointed out how it looks like he has tears in his eyes in the falling angels scene.
So one could add that to the argument that Dean is as important, if not more important, than heaven and his family to him. And it’s not all humanity (though he does love humanity), but it’s Dean in particular that he loves.
Okay, so in summation, Metatron said that Castiel is in love…with humanity. But the very next episode, he says really, even though Castiel says he’s working for heaven, his ultimate goal has always been to save Dean.
This lines up quite well with the first three episodes of season 10, where Castiel made Dean his priority, even though his own grace was fading and Hannah kept asking him for help with the angels. He was still trying to reach Dean.
So, it is never said that Castiel is in love with Dean. But subtext. It’s blatantly obvious. He’s in love…
side note: I think perhaps it’s very telling that Dean was preoccupied during “I’ll Just Wait Here Then” – it’s the only song we didn’t see him reacting to. It’s also the only one of the three original songs that, after the first couple of lines, doesn’t get intercut with…