There is no other person, be they human or hollow, who can bring out so many different feelings in Orihime, as the Cuatro Espada.
From being her jailor to becoming her companion in a world that was empty of companionship. The emerald eyed Espada had been with her for the whole time she had been Aizen's prisoner. Seeing him turn into ashes, unlocked the cache of feelings she had for him. Too late as she thought, but with the sudden appearance of Ulquiorra in the Living World, all bets are off again.