What is the common ground between being keen on purifying the inner self before adorning oneself with a ring, and the idea that outward resemblance brings about inner resemblance? And is this understanding correct?

A Muslim should rectify both the outward and the inward, in compliance with the words of Allah Almighty: "O you who have believed, enter into Islam completely." And although outward resemblance gradually affects the inward, it alone is not sufficient. A Muslim must purify their soul and improve their character through striving and seeking Allah's help. As for beautifying oneself, it is one of the customs that does not involve showing off, and one may be rewarded for it if the intention is good, such as emulating the Prophet, peace and blessings be upon him.