[...gdit Rokurou she's trying not to tell you so she doesn't make you think that you have to be in love with her or something!!! ETRO HELP HER THINK OF SOMETHING because this is not what she had in mind here.]

You... got jealous over something. I don't know what, but you came and visited me and lost your mind over something else while we were talking, and you left.

[It's. Not entirely a lie. He was jealous. But she can play it off that she didn't know what. Maybe he'd take it like he was looking for advice and... that would be it?]