* Surprise: The speaker is hearing something that is unexpected or surprising. This "astonishment" could be triggered by the content of what is being said, the speaker's tone, or some other aspect of the situation.
* Intensification: The word "increasing" indicates that the surprise is growing stronger as the speaker listens. The listener is becoming more and more surprised as they take in more information.
* Engagement: The fact that the listener is paying close attention, listening intently, suggests they are interested and engaged in what they are hearing. They are not just passively listening, but actively processing the information and being affected by it.
To understand the phrase better, we need more context. What is she listening to? Who is speaking? What has been said before this phrase? Once we have more information, we can better understand the nature of her surprise and the reasons for her astonishment.