When looking up phrases such as 'what makes a good leader?, or 'how to be successfull', you'll undoubtedly find a number of lists detailing the specific traits, characteristics, or in our case 'qualities', that go into making a 'good leader' or 'successfull person'.
Since the qualities that make up a 'good leader' or 'successfull person' are numerous and variable, these lists tend to be high-level overviews of a 'core set' of qualities that these people have in common.
I felt taking a similar approach would help when discussing something as nebulous as 'user confidence'. As stated earlier, a user's confidence is effected by a number of overlapping, often-nebulous, factors. Therefore, to simplify and ground a discussion on the topic, I've grouped the common factors into the following 3 qualities: