INSOUCIANT

unconcerned, carefree, heedless

marked by blithe unconcern
SYN - casual, nonchalant
"An elegantly insouciant manner"

"What had really gotten to him was the way his topic was treated with such an insouciant attitude."

"The ladies loved him because he treated them and his fame in such an insouciant way, giving off the persona that he didn't need either."

"When he introduced himself he tried giving off an insouciant vibe so that he wouldn't show how much he wanted this and the lengths to which he would go to get it."