To be confident in your work is to tell the truth:
Lacking confidence while applying skills, product development or engaging in sales conversations means the truth is suppressed. There is meaningful, ethical advantage that a project, company or individual could benefit from that you wilfully withdrew, because of that lack of confidence.
An equal but opposite concern is when over-confidence appears, which augments truth with delusion. Here the same meaningful, ethical advantage is still available, but misrepresented so the project, company or individual can’t critically or clearly assess a situation, because of that over-confidence.
Being truly confident in our work avoids both of these pitfalls. From confidence comes a clear, accurate representation of the truth, impeded by neither suppressions or augmentations. The work is what it is, it’s merits accurately and completely articulated.
Are you (truly) confident about your work and your wares?