We can consider the sentence presented above as an example of descriptive structure. The descriptive structure is one where the sentence presents information that describes what an element is and is not.
As we can see from the sentence shown in the question above, the quality of truthfulness is described as something complicated to define. In this case, the sentence has a descriptive structure.
It is important to emphasize that the textual structure refers to how the information in a text is organized.
