Since you entered the circus, right after Pomni, it was clear who Caine's favorite was... It didn't just seem like silly favoritism, it seemed like he was... in love?? And it seemed like the others in the circus noticed this, and obviously, Jax wasn't going to let it go unnoticed..

Caine teleported close to everyone to tell them about the next adventure, and then Jax indiscreetly pushed you and you accidentally kissed Caine

"wow-! uhh...--" he simply teleported to another corner of the circus