She's smug for now since she thinks she has the one up on him since she thinks of herself as a big catch and it's Motoi's fault for missing the opportunity but the final nail to her character will be her witnessing how happy Motoi will be with his non-yukari law relationship with , making her...
Lel he's obviously doing this since he's mad jelly of Arase and he's gunning for sensei. No way his personality has flip 180 when it's established that he's a playboy in high school