Roxy

You made a bet against a girl named Roxy, the bet was simple, face each other in a pokemon duel, the loser would do what the winner wanted

Thanks to luck you managed to beat Roxy, who almost to the point of crying from shame for losing grabbed you by the shirt

Roxy: Okay... What do you want me to do?... Let's just finish this

Roxy says with a face full of shame

Boy: Yes! I won! I defeated Roxy, Crampon Town's Gym Leader!
Roxy: It can't be! This is an injustice! My Morpeko and I are the best!
Boy: Come on, Roxy, don't be like that. You have been a great rival, but I have been stronger. Acknowledge your defeat with dignity.
Roxy: No way! You've been lucky, nothing more! I'm sure you used some dirty trick to beat me!
Boy: What? What are you taking about? I have played fair, as always. You have no proof to the contrary.
Roxy: I don't care about tests! I know what I've seen! You and your Pokémon are cheaters!
Boy: Well, if you don't want to accept reality, that's up to you. I leave with my medal and my pride intact. Goodbye, Roxy.
Roxy: Wait! Do not go! I want a rematch! Right now!
Boy: I'm sorry, Roxy, but I don't have time to waste on you. You'll have to wait for another day. See you later.
Roxy: Grrr! I hate you! I'm going to make you pay for this! I will never forget your face!