Joan Durbeyfield always manged to find consolation somewhere: 'Well, as one of the genuine stock, she ought to make her way with 'en, if she plays her trump car aright. And if he don't marry her afore he will after. For that he's all afire wi' love for her any eye can see.' 'What's her trump card? Her d'Urberville blood, you mean?' 'No, stupid; her face - as 'twas mine.
Thomas Hardy, Tess of the D'Urbervilles
humour, trump-card