The confidence of a person in building his skills and special abilities will depend on the length of work experience he has accumulated.
His personal marketable attributes will sure be noticed, and these are the immediate qualifications that most employers immediately look at, especially in time of needing to recruit sensitive positions in an organization.
It is easy to notice when a person is truly up to par with his claims as far as his bio-data or resume contends. Aside from the usual background checks that most companies resort to, personality wise, it is easy to spot during an interview with the person if he is truly sincere and authentic when it comes to his qualifications. The right mixture of confidence and job knowledge is the perfect recipe to be able to contribute properly in any job undertaking.
Here are some links to help shed some light into such issues: