Where large sums of money are concerned, it is advisable to trust nobody.

The line distills a recurring Christie theme: money is a powerful solvent of social bonds and a frequent catalyst for deception, betrayal, and violence. In her detective fiction, inheritances, insurance payouts, and hidden fortunes routinely motivate otherwise “respectable” people to lie, manipulate, or kill. The aphoristic warning suggests that financial stakes change the moral calculus—trust becomes a liability because self-interest intensifies and appearances are easily staged. It also reflects the genre’s logic: when money is central, everyone has a motive, and prudent skepticism is the first step toward uncovering the truth.