Sailor Jupiter confronts Tuxedo Kamen because he's been flirting really visibly with Sailor Moon (remember she still thinks he's Masato Sanjouin because magic identity shenanigans), except it's Mako so she's delicate about it, and it's Mamo so he has no idea what she's on about, and Mako ends up with her heart broken and Mamo ends up awkwarding out of the conversation he doesn't at all understand.