If your opponent declined your pawn offer in the Danish Gambit and brings out his light square bishop in order to exchange yours light square bishop with his one then the best plan you should make is to target his queen side rook with the combination of light square knight, light square bishop and Queen.
The chance that you will win the game when your opponent brings out his light square bishop for the exchange of your own light square bishop is very close to 70%.
In below game my opponent refuses to accept my pawns offer and he ends up losing the entire game.
Bringing out the light square bishop to defend against Danish Gambit is totally waste of time! Never do that if you are playing in a really high level chess game.