When you ask someone to do something for you, it is best to give the real reason for wanting it rather than giving reasons that might give more weight. Anyone who completely trusts anyone else is asking for trouble. It is hard to get ahead without cutting corners here and there. It is safest to assume that all people have a vicious streak, and it will come out when they are given a chance. One should take action only when it is morally right.
Most people are basically good and kind.
There is no excuse for lying to someone else. Most people more easily forget the death of their father than the loss of their property. Generally speaking, people won't work hard unless they're forced to do so. R. Christie and F.L. Geis, Studies in Machiavellianism. Academic Press 1970.