The striker has struggled since the start of the Premier League season.
Arriving from Birmingham in the Championship, Adams has not scored in the opening four games of the season.
But Hasenthuttl is convinced Adams will come good.
He said to reporters about Adams: "He is a little bit unlucky sometimes with his actions. The pre-season was much easier for him where he scored immediately and this gives you self-confidence.
"He is waiting and working hard and he didn't score so far but I'm convinced about this guy.
"He's a very positive guy and he needs a goal but when he works like this in the future it will come I'm sure."