Mancini said he would "probably" try to sell his fellow Italian after his sending-off at Arsenal last month but the pair are now reconciled.
The City manager told Gazzetta dello Sport: "Mario has been very clear and I reiterate: Balotelli will remain at Manchester 101 per cent.
"I am confident he will have a great European Championship.
"I hope Mario will be the leader of the national team because he is the best Italian striker.
"He just needs to make his brain work. That is his only problem."