The first example is moral. It depends on what we know about the person, their family and upbringing.
The second example is technical. We would need to know what kind of jobs the person had done before and, perhaps, what kind of training he had.
In order for one to trust another, their worth and integrity must be proven over time. That applies especially to the first (moral) case.Trustworthiness in technical matters may be identified by attributes such as reliability, dependability and qualifications.