Having faith in other people depends heavily on trust and experience. Trust has to be gained and maintained in order to have faith in someone. The experiences of trust or distrust will effect your faith in that person. To have faith in someone means to constantly trust them. In the past you have seen that they are worthy and capable of your trust, in the persent they have your trust, and you can trust them to do things for you in the future. But one event of distrust can cause the past, present, and future trust to be destroyed, and the process of gaining trust must start anew. Even after distrust there can be faith, faith that the person will once again gain your trust because in the past you have found them worthy of it. However many other factors effect the ability to have faith in a person.
Understanding philosophers like Hobbes and Neitchze put into question the real motives for why people act trust worthy to another. These theorys on how people behave with one another are pessimistic but not illogical. Hobbes believes that people do not have free will and are no better than animals while Neitchze believes that the only real motivator in the world is power. These claims oppose each other but they share the common idea that people do not act out of virtue but rather just on desires. This fact led me to question the real motives for why people act the way they do towards me. I could take the Nietchze approach and see that those people are just trying to further their power or I could take the Hobbes approach and say they are only doing it as instinct to survive. Niether of these options are very consoling but both of them are based on facts. If people only wanted you to have faith in them so they could further their own causes no one would have faith in another person. Faith in another person cannot exist if it's existance is only to further the goals of one individual and not both the individuals involved in the relationship.
As scientists learn more and more about the human mind, it is easire to change human emotions into some quantity of nerve impulses sent to the brain and different protiens being released. These scientific revalations cause me to wonder if people that I put faith in are not just programed to care for me because that is their nature. Pyscologists can explain why humans act the way the do towards one another and what they are truly thinking. The state of other people's minds also makes it difficult to put faith in others because you can never truly know what they are thinking and that puts pessimistic hypotheticals into the mix. You could have studied pyscology so rigerously that you may begin to believe that all people are only acting towards you in certain ways based on their mind and not their emotions.
How the mind works is the major challenge of faith for me in regard to relationships with other people. This knowledge questions why people act the way they do with a pessimistic spin on it.