How did the lawyer feel when he finds out that he has successfully learned six languages in "The Bet"?

If I successfully learned six languages, I would feel ecstatic, thrilled, and probably quite proud.  A reader would assume that the lawyer would feel the same way.  Perhaps he does, but the text doesn't seem to indicate that he felt those feelings.  

The lawyer made a bet to prove that capital punishment is less humane than life in prison.  In order to defend his opinion, he agreed to spend fifteen years in solitary confinement....

If I successfully learned six languages, I would feel ecstatic, thrilled, and probably quite proud.  A reader would assume that the lawyer would feel the same way.  Perhaps he does, but the text doesn't seem to indicate that he felt those feelings.  

The lawyer made a bet to prove that capital punishment is less humane than life in prison.  In order to defend his opinion, he agreed to spend fifteen years in solitary confinement.  He is not allowed contact with anybody, but he is allowed to read and study as much as he wants.  During his sixth year in prison, the lawyer begins ravenously studying languages.  

In the second half of the sixth year the prisoner began zealously studying languages, philosophy, and history. He threw himself eagerly into these studies -- so much so that the banker had enough to do to get him the books he ordered.

After four years of studying, the lawyer feels that he has mastered six languages.  He writes the banker a letter in six languages and asks to have the letter proofread by experts.  If the letters are error free, the banker is to fire a pistol shot in verification.  The lawyer wrote in is letter that if his letter is error free, he will feel that his efforts have not been wasted.  

That shot will show me that my efforts have not been thrown away. 

Based on that, when the banker has the shot fired, I believe that the lawyer mostly felt affirmed.  He set out a goal for himself, and he achieved that goal.  There might be some pride there, but I don't believe that there is much pride.  I also believe that there might be some relief.  The lawyer was obviously curious to know information about how well he was learning.  When he learned that he was successful, I'm sure there was relief.  I'm always relieved when my teacher evaluation comes back and says good things about what I do in the classroom.  I believe the lawyer feels the same way.