Disclaimer: I do not own Harry Potter.
By Silver Sailor Ganymede
She knows he is not loyal. He never has been and he never will be; after all ambition and loyalty would be a clash of traits, would they not? If one is loyal and ambitious they will, in the end, get nowhere. He is ambitious, cunning, sly; perhaps that is the truth but perhaps he is forced to be that way, she cannot tell.
Hannah had always been good at reading people's emotions but she could not see the truth in him, just his ambition and thus disloyalty, though whether it is real or façade she cannot tell. She does not care though; her loyalty would make up for his lack thereof, and perhaps he could combine loyalty and ambition, just perhaps: she can never tell with him.
Hannah, however, is a Hufflepuff, and Hufflepuffs are loyal. Hannah knows that no matter how he seems to be, she would be loyal to Draco Malfoy.