Charm can be deceptive and physical beauty will not last, but a woman who reveres the Eternal should be praised above all others. (Proverbs 31:30 VOICE)
There is one trait which makes an individual absolutely irresistible and that would be the deep, truthful reverence of the Lord as the center of one's life. The individual who makes Christ the most important part of their life may not always be the most extroverted, "in the lime-light", kind of person, but they are trustworthy, well-balanced, and overwhelmingly joyful at the core of their being.
"Inner beauty" as some might refer to it is not something we "possess" as much as it is in being "possessed by another". It is Jesus in control of our hearts which brings forth that inner beauty in ways others may not be able to resist!
When we focus on our inner beauty, the outer beauty is something which doesn't count on us wearing the latest of styles, having the most perfectly manicured nails, or even sporting the most flattering of hair styles. Inner beauty begins to reflect in our actions - something which speaks much louder than any of the "outer adornments" we ever might pursue. Inner beauty is what gives us true "charm" - that which has some "appeal" which cannot be denied.
There are times we spend more time and effort on what we consider to be the things which will "keep us young" or "make us attractive". Sadly, we ignore the most significant of actions we can ever take - spending time with Jesus, just nuzzled up to him, drawing from his strength, learning from his words, and taking in his peace. Those moments do more to "build us up" than we might realize - changing our "sour disposition" into a much more "pleasing" disposition. What attracts us to people isn't their talent as much as their "disposition". Our disposition is the dominant (prevailing) tendency of our spirit - some call it our "prevailing attitude". Get the spirit aligned with Jesus and the "prevailing attitude" of our lives changes!
We may not think much about "charm", but if scripture records the "beauty" one might describe in an individual, we might just do well to consider the value of a "disposition" bent toward grace! Just sayin!