Okay, so I have some thoughts about a certain Miss Phryne Fisher and Detective Inspector Jack Robinson, so I'll just leave this here.
Crypt of Tears looked at two of the main roadblocks that used to be in the way of Phryne and Jack's relationship in mfmm:
Jack's jealousy: Phryne has married a maharajah, and Jack feels hurt because she told him before that she wasn't the marrying type. This is resolved when Phryne finally explains that it was necessary to save the maharajah's life.
Phryne's recklessness: Oof. Jack went 6 weeks thinking Phryne was dead, which is... pretty bad. Phryne usually flings herself into danger and Jack tries to pull her back. It seems like Phryne starts making a point of asking Jack for help instead of trying to manage alone (she asks him to go to the church with her; to help her out of the quicksand; and to kill the "tarantula").
The main issue in their relationship has always been communication, though. They can banter and insinuate like no other ship, but they never used to state their feelings or needs outright. This actually leads to the other issues they have.
They usually understand each other so well, which leads to Phryne doing things in "blind faith" and expecting Jack to understand.
The fact that they've never clearly defined their relationship leads to Jack's jealousy (and the great scene where he's drunk in s3). It also causes Phryne be reluctant of explaining herself to Jack or asking for his help, because she is scared that that would imply that she's surrendering some of her self-suffeciency.
This is all resolved in the final scene.
Their confessions in s3 ep8 had been romantic, but pretty vague. "More like a romantic overture" and "Come after me, Jack Robinson" were great, but when we look at the movie, it didn't appear to have cleared anything up. However, their confessions in this movie finally smooth things over. Jack makes it clear that he doesn't expect her to marry him, that all he wants is her heart and that she has his. Phryne tells him that he has her heart as well. They've finally defined where they stand and what they expect of each other.
