[Taken]

I think if you would have watched the school festival arc, you would have realized that the friendship of Taiga and Minori is very strong. For the good part of her first year in school, Minori is like the only friend Taiga had. To add to that Taiga is very separated from her parents.

And very early on, Minori understood that Taiga and Ryuji like each other (ep 8 being most obvious). It's just that they didn't realized it. She was also aware that the Ryuji she has fallen for was the Ryuji that cared very much for Taiga.

She even had her worse fear came true in ep 18 in a way when she broke something very precious to Taiga. It was a parallel to what she feared if she were to "take away" Ryuji from Taiga.

But eventually she found the way to resolve all these in ep 24. Her confession, her clarification and her courage to move on. That kinda earned another new respect with the fans and of course that moved the story on as well.