Hearts have rejected a £1.5million offer from Wolves for Berra this summer, and turned down two Burnley bids for Driver.
Hearts play Glentoran in a Belfast friendly on Monday night where their Hungarian manager will get the chance to see the pair in action.
"They have quality. But there is time to develop them and I can give them the right direction.
"It can be easy for a lot of players to smile at money and go to a new club but they shouldn't believe life is so easy.
"The players can develop here, play good games and gain confidence and grow more.
"After some years maybe they can then choose bigger clubs. But my intention is to keep these players."