Bilbo earns the respect of the Dwarves he is traveling with by being both brave and resourceful. He overcomes a lot of dangers and becomes a much more confident adventurer, something that would not necessarily be recognized in the Shire. If the first film is a story of how a Hobbit can go on an adventure and thrive, earning the respect of his Dwarf companions, the second film is that same Hobbit realizing just how big and dangerous the world really is. But how do you show that in a visual medium?
Possible spoilers after the break
The answer lies in the Desolation of Smaug, the place, not the movie title. This is the region of land surrounding the Lonely Mountain that was incinerated when Smaug first destroyed Dale and Erebor and has remained barren ever since. It is labeled on Thror’s map and described by Thorin during the Unexpected Party. Most of the other dwarves have never seen the Lonely Mountain or the Desolation of Smaug, but they’ve been raised on the story. For Bilbo, this is some far off land that he can’t quite wrap his mind around because he has no reference point in his own life.
Through all the adventures leading the Company to Laketown, Bilbo has not only proven himself to his companions, but he has become a more confident member of that Company. But then they finally leave Laketown for that final journey to the Lonely Mountain and for the first time, the immensity of the problem at hand becomes evident. All the land near the Mountain is in ruins, with very little growing, even though it is 100 years or more since the Dragon arrived. The silhouette of the Lonely Mountain looms ever closer as the presence of the Dragon looms ever closer. The same feelings can be shared by many of the Dwarves as well, seeing the Desolation of Smaug first hand, it drives home what they had always been told. Smaug is an efficient and ruthless destroyer of life and is capable of wiping them all out in a heartbeat.
But the Company keeps on going, whether through Thorin’s strong will, or some great courage within, even though they now feel somewhat exposed on that trail to the Mountain. Once they finally figure out the secret of the hidden door, the Dwarves look to Bilbo to do his job and burgle, and after some trepidation, he goes in. Knowing the Desolation outside, Bilbo masters himself and does what he was brought there to do. It is the knowledge of the Desolation of Smaug that he must overcome, because as yet, he has not seen the Dragon. It is only through the observation of the Dragon’s fury that he has any idea of the scope of what he may face at the end of that tunnel. Facing that great unknown, after seeing what his fate could become, is Bilbo’s defining achievement. Bilbo overcomes The Desolation of Smaug.