MC was like, "if you knew that from the start then why were you crying/acting jealous and shit, was that all an act?" Well, remember on the earlier chapters when Robia was introduced, he cheated on the Princess, right? So his suspicion started when he started to develop feelings for the transmigated!MC. He was like, "...what did I fall in love again". But then he realized, she's way too "sweet" and different from the Princess he knew. So yeah, the chapter ended with Robia saying that he wants to be with the transmigated!MC, not the OG and he pledged to prove it.
I DID NOT EXPECT THIS AT ALL!!!! I THOUGHT HE WAS JUST REALLY OBSSESSED WITH THE OG THATS WHY HE NOTICED. DAYUMMMM. But he's a bit sus so Idk