Sigma males approach women differently than most men. They are not driven by looks, but they find beautiful women to be very alluring. If a woman is wearing nice clothes or has nice hair, that will not be what interests them.
What matters more is her personality. Many sigma men show their interest in women by first seeking common interests.
Sigma males are often intense people who tend to take almost everything in life seriously.
They will not approach a woman and flirt in a funny or easy-going manner, but they can be intense when flirting.
This intensity causes them to come off as very formal at times when meeting new people, even with women.