When you successfully cast Divine Blessing on a weapon, the only result is:

"You furrow your brow as you look through your possessions."

It would seem this should also have an echo telling the paladin what the change was, similar to the phoenix brand, or that the item shines with light, or such. Instead, whether you lost concentration, or succeed, you just see the burrowed brow. For failure, you get a message, for success you do not.
*SNIP*