I would like to ask what is the most important factor that Human Resource Personnel looks for when they Hire Employees?

from my own side  .. Smartness + Enthusiasm = all the above.

( Qualification - Experience - Training - Expertise ) doesn't mean the person understand what he is doing or he is ready for this job.

I would rather hire a candidate who is well expertise in the field of knowledge what company is seeking for taking into account his smartness and enthusiasm irrespective of what experience he has earned.