This is why governments have to be careful not to oversupply money or devalue it in other ways (e.g. like Henry VIII debasing the coinage in 1542).
https://en.wikipedia.org/wiki/The_Great_Debasement
People don't like it if money loses its value too quickly due to inflation, it means they have to spend it straightaway, as in Weimar Germany in 1923.
https://en.wikipedia.org/wiki/Hyperinflation_in_the_Weimar_Republic
This is all a matter of trust as you say. I would like to see an argument for unlimited public spending that addresses this properly.
