> Also to note, why was the US trusted before?

Trust was never absolute. What we trusted was that the US would act rationally to further their interests. The US benefited tremendously from economic development across the world (industrialisation, free trade, rebuilding after the wars, etc). Sometimes the US government miscalculated (like in Iraq), but there was nothing really destructive like what Trump is doing.

Even when we disagreed we could still talk things through and agree on other things. Now, you have Trump insulting allies and praising ennemies every day. Of course there is no trust.