see the colour of somebody's money

see the ˌcolour of somebody’s ˈmoney

(British English) (American English see the ˌcolor of somebody’s ˈmoney) (informal) make sure that somebody has enough money to pay you, especially if you think they might not have it: I want to see the colour of his money before I start doing such a dangerous job for him.
See also: colour, money, of, see