So he doesn't find bertia's attempts to be interesting anymore or the heroine's??

I think the translation made it really confusing but from what I got from it, he had so much fun recently (from Bertia) that the Herorine’s desperate attempts aren’t interesting. I think in the original plot, the prince liked the Herorine because of those desperate attempts but now he likes Bertia instead. ٩(๑❛ᴗ❛๑)۶

damn i think that he meant Bertia is not as interesting as before.

The prince thinks Bertia's desperate attempts to pit him together with the heroine is less interesting because he's finding that he may have feelings for Betia (even though he hadn't realize yet) Lol, but I think your interpertaion on the lines seem spot on though.(๑•ㅂ•)و✧

Maybe he means it is uninteresting to see bertia be that desprate in matching him with the heroine. That's why he said it's uninteresting now(bertia plotting) yet he was interested in more troublesome things (bertia did) before.

Thanks guys i get it now

hope that Bertia in the sooner chapters will realize the prince is getting tired of it lol, Cecil likes her but is too dense himself to notice it i guess.

bless i was scared that he was starting to lose interest in her