Before the battle, she and Misty promised to give their best in the battlefield. The following day, Trinity proved to be a powerful Water Pokémon trainer, as she defeated Misty quite easily. The following day, she battled another trainer, but lost.
Trinity's Gyarados was the first one that Trinity used in her battle against Misty. It is unknown if the Gyarados is her main pokemon, but it is very likely.