Allaah subhanahu wa taa'la has installed trust in every human being by default. Man uses this 'facility of trust' by intelligence and experience and understands whom to trust and whom not to. A newborn baby doesn't understand anything his guardians do for him, but after few months he start reacting to their services with a smile and start recognizing their faces. After some more months, he does not turn to the people he doesn't know rather he crawls to the people he recognizes and trusts. A newemployee doesn't know about the nature of his co-workers on the very first day but within few months he understand which co-workers are trustworthy and which co-workers are the 'spoons of the manager'. Therefore, trust is developed in a human being slowly and gradually as per the experiences. The Creator has not created man to live alone, all by himself and away from everyone and everything. The world that he is created into comes as a package to him, and he will have to learn, with his intelligence and experience, whom and what to trust, and whom and what not to trust. And this comes naturally to every human being, whether he realizes it or not. The One Being whom one must absolutely and completely trust, is the One Who Created him and everything else that is in existence; for there is no better well-wisher of man thanthe One who created him, and gave man everything, more than he needed or deserved. Allaah subhanahu wa taa'la says, If Allah helps you, none can overcome you: if He forsakes you, who is there after that that can help you? In Allah then let believers put their TRUST. (Qur'aan 3:160) And put your TRUST in Him Who lives and diesnot; and celebrate His Praise; and enough is He to be acquainted with the faults of His servants (Qur'aan 25:58)