b3 is a weak move, doesnt help white position.
White has to find a way to develop, and then 5.Nc3 is the move, with the idea 5...Qxb2 6.Nb5 with problems for black...
For instance :
Why not playing simply 4...cxd4 5.Bxd4 Nc6 when black already has the upper hand.
More usual for white is c3 before playing Be3 :
And as promised, here is the game I just finished, where I played the same opening shown above! :)