Sentence:  Afraid at one and the same time that his work might be turned down - which would be a blow to his pride even though no one knew he was the author - and that the work would be accepted , and then that his violent feelings in the <WSD>matter</WSD> would certainly betray how deeply concerned he was in spite of himself . 
Meaning of the word marked with <WSD> tags:  a vaguely specified concern