Jonas is conflicted when he receives his adult assignment. The Giver was a job nobody knew a lot about, and definitely not something that young people knew much about. The fact that he got singled out for this very job is also awkward in a society that thrives on every person being the same. Asher's hesitation in congratulating Jonas is because Asher doesn't understand Jonas' job any more than Jonas does. Also Asher realizes that being the Giver makes Jonas different, once again, being different is not typical in their community. So, he is alternately proud and embarassed.