Why didn't Adso take the girl with him at the end?
He seems to hesitate quite a bit and is clearly inclined to have a female companion in his life. That is, it is clear that he's not becoming a monk in order to shield himself from his sexuality, but rather because his father wishes it. After his experience at this abbey and seeing all of these sick wretched monks you'd think he'd want out of that lifestyle, to live a normal life and have a family. Of course he doesn't know this girl at all, he's only just had tender moments and a sexual encounter with her, but you'd think his pity for her alone would want to make him "save" her, no? For the sake of not having a hollywood ending I am glad that he does ride away, but still it's puzzling including how he says he never regretted it.
This movie is a masterpiece!