Tina is GOOD and PURE and Blue likes her a lot. He definitely thinks of her as a little sister type. She reminds him of young trainers that he's played mentor to in the past, whether as a Gym Leader/Battle Legend taking challengers or a traveling trainer on the road. She has that wellspring of optimism and wonder in her eyes that makes him feel nostalgic for the first time he and Red left home. (As a Champion trainer, you can lose sight of where you started from; Blue really enjoys watching up-and-comers as a way to keep himself grounded. For all his bunk, he's not actually as arrogant as he acts.)

Tina reminds him the most of how people are back home, and he wouldn't hesitate an instant to help her get her first Pokémon! He thinks she deserves it.