America had a positive perception among the countries it offered loans to help rebuild (Western European countries, Japan). Keep in mind that a lot of the colonial and slavery based wealth that Europe accrued was essentially transferred to the US during WW2. By the end of world war 2, the British empire was essentially bankrupt. Most of the world's gold reserves were now in the US and greater than 50% of global industrial output was US based so the economic outcome was immensely positive for America. It makes sense that your allies would gong your drum when you are offering to finance their reconstruction.

Essentially outside of this sphere knew the US would simply become the continuation of the British / other colonial empires and history has shown that to be true.