Creating false evidence

In the end, Jason didn't have much to tell her. 

He simply shared the truth with her that he was pulled towards a specific dungeon, in which he had solved various trials before he received an inheritance and many great rewards.

However, the more he spoke about the content of the trials, and what kind of passing score he received for the things he did, the more serious Jennifer's expression became.

Once he concluded his story, she was staring at him in doubt, not sure what to say anymore.

She was already doubtful when Jason spoke about the city-like treasury, but the moment he said that there were several [Sun] ranked techniques out of which he had chosen one, Jennifer was utterly dumbfounded.

But, her confusion only increased when Jason said that he didn't take any of such techniques because he was interested in a gradeless technique instead!