Misty, however, is more eager as to whether her sisters mentioned anything about her to Dorian. Much to Misty's horror, all Dorian had heard was that the girls were sad that the baby of the family was such a loser. Misty bites everyone's heads off and the argument turns to who loves Water Pokémon the most. Dorian disputes Misty's claim, and she challenges him to a battle, seeking to prove who the best trainer from Cerulean really is.
She's just curious about if her sisters told Dorian anything, only to find out she was a "loser".
She blushes because:
Dorian thanks them sincerely, and promises to pass on how well Misty is doing to her sisters when he visits Cerulean City. The group bid farewell to Dorian and continue on their way.
Misty blushes after hearing how "good" she is, basically.