I want to provide a possible theory for the Green Prince: on a soul level, he and his partner might be the same being.
The primary basis for this theory is the description "Two children born entwined, apart," the shape of the Conjoined Heart, and Hornet's evaluation of them: "For one to love another so similar to themselves, is that selfless or vain?"
I believe they were meant to be born as a single individual, but due to various factors, they were born as two separate beings, hence described as "born entwined, apart." In a sense, they are the same bug, only complete when together; thus, the Conjoined Heart takes the shape of two leaf-like objects touching each other—it is the Green Prince's heart, but also his and his partner's heart. Perhaps it's two halves of the same being who fell in love: "For lovers born on beat exact" may not simply refer to them being born at the same time, but also imply that they are "too similar"—they love each other, but also love another version of themselves. This better explains why merely loving each other results in them being "forever cursed."
This theory makes Hornet's comment about them seem less harsh; she might simply be stating her objective interpretation (though somewhat sharp). It also explains why Team Cherry designed the Green Prince's story to end in death—without his partner, he can never be whole again; he cannot live alone, and only dying by his partner's side is true redemption for this character.
The Green Prince is destined to die, but I also emphasize that Hornet's actions are not some brutal atrocity, nor can they be called "assisted suicide" or "mercy killing." Hornet didn't take his heart to make him die. Killing him was not her goal; she was simply carrying out what she believed she should do in the process of saving Pharloom (whether collecting hearts or honing herself), and the Green Prince happened to use this as an opportunity to recall the beauty of the past—that's why he wasn't grateful to Hornet for invading his memories, but also not surprised, and didn't resist or struggle beforehand. The Green Prince simply used Hornet's actions to let her witness the most glorious moment of him and his partner, while conveniently achieving his own desired outcome—dying together with his partner.













