***For women: She dresses tzniusly.
For real? No, that shows more often than not that she is conforming to society. Fear of the neighbors or the shadchanim is more like it.
Besides, there are different shittos. What one community considers tznius, another one would consider not tznius.
And, I find it very disturbing to gauge a woman’s level of fear of heaven based solely on dress. That’s very superficial.
Especially since nowadays, it is so easy for people to hide behind a levush of piety. You have no idea what is really going on inside. She can be doing it mindlessly by rote because that’s what everyone else in her society is doing. While having horrible midos, never davening, no connection to Hashem, and a Yiddishkeit that is dull and lifeless. And no fear of heaven at all.
And there are people that dress that way just for shidduchim even though that’s not who they really are at all.
All in all, I’d say it’s a very shallow way of judging people’s yiras shomayim. (And I don’t think we necessarily can really judge anyone’s yiras shomayim accurately.)