commonness; the common touch
Refers to the quality of being like ordinary people, approachable, or having a down-to-earth character. Often used to describe a person's personality or the atmosphere of something.
His common touch is loved by many people.
This politician doesn't seem to have the common touch.
親しみやすさ is a more general term for approachability or friendliness, whereas 庶民性 specifically implies a connection to ordinary, everyday people.
Compound of 庶民 (common people) + 性 (nature, quality).