While betrayal is always an unpleasant experience,the effect of the betrayal on the betrayed person depends to a very great extent on the relationship with the person who has betrayed you. If it is a business deal, it is relatively easier to handle the betrayal as the loss is mainly financial.
Many times employees or people you hire for work betray you soon after you have paid them or entrusted them with an important assignment. One way to deter/prevent this kind of betrayal is by making these associates sign a non disclosure agreement. It also makes it difficult to trust people in future and hire new employees /contractors.
However, when it is a relative or a close friend who betrays you , it changes the outlook of the betrayed person towards life in general. The person whose trust has been betrayed becomes extremely cynical, and will find it difficult to trust or even become friendly with anyone for the rest of his or her life.