Okay so you know how Kanaya used to have feelings for Vriska? And also how Aranea used to date Porrim (She called it a red-fling, but still...)? I swear I'm going somewhere with this, but hear me out on this headcanon.
Kanaya and Aranea initially developed feelings for each other because they reminded each other of their respective ex/ex-crush.
Kanaya would so avoid/deny it for as long as she could because she doesn't want to risk that heartbreak again (and also probably because Aranea looks so much like Vriska). While, on the other hand, I feel like Aranea would be all for pursuing. But at the same time I feel like Aranea would also kinda deny it at first? I dunno. I just think Aranea would accept those feelings of hers much faster than Kanaya