Whom to trust and how much to trust??

All of us at some point in life have pondered this question:

Whom to trust and how much to trust?

In spite of thinking very hard, we never got a satisfactory answer, even if we thought we have an answer, very soon an incident took place that made us doubt the answer we arrived at. Before I delve deeper into this issue, I would like to ask all of you, how easily do you trust?? And what are your criteria to trust someone??

According to one book I read, I faintly remember that the author mentioned, we tend to trust people who fit in our blueprint of what kind of personality we wish we wanted to have or we trust our favorite people, actor, actress or anybody whose personality appeals to us more easily than others. Intuitively, when our favorite actress or actor endorses a brand we tend to see that product(s) with more benefits than pitfalls. Yes!! This means we tend to trust the person we are attracted to more than others. I believe this is a primary reason why many people after some time have trust issues because they trust too easily and too soon. So back to the primary question whom to trust and how much to trust? There is no single answer to this, in my opinion, we must give ample amount of thought before you trust anything or anyone. The longer you take to trust the longer it lasts and deeper it grows.