it's a partial semi bluff, b/c you don't mind if he folds here, but it's also about getting paid off when you make your hand. If you hit your king or diamond falls off (especially a paint diamond), can you still stack him?

These considerations, plus the fact that you have 12 live outs twice and there is money in the pot already (so you're coin flipping, but getting an overlay) have to make pushing +EV.