When Amon realized that Diana was not speaking, he could not help but feel a little helpless. It was not as if he could actually force Diana to speak.
In any case, since she did not want to speak, then there was no need for him to ask any question. He had already lost the group that he had come together with, but at least, he had already gotten Diana.
Additionally, the group that Diana belonged to during the time that she was in this world did not come after her. That implied that they might have given up on her.
Currently, he was far away from where the elves were located. For that reason, if he was attacked by the other races, it was definitely going to be difficult for him to be able to go back without suffering. So, it was better for him to go back for now, then he would think of a method of coming back to avenge the group that he had come together with.
