I never expected any sort of success with 'Mockingbird'... I sort of hoped someone would like it enough to give me encouragement.

This quote means that the speaker did not expect that their work of art (in this case, a Mockingbird) would achieve much success, but instead, they were hoping that at least one or two people would enjoy it and show appreciation. The speaker was hoping for encouragement from someone who liked their work, even if it didn’t become a big hit.