so flirt is an intro to relationships, its not necessarily a defined thing, just a side comment (which if your playing as a flirty character is not a bad thing). But like an agent gets to marry a voss and receive letters from them plus a romance t with the chiss also changes some dialogue and again he sends you mail. it adds to the personal playboy/girl rep in character roleplay. Plus, not all characters have to get married they can be untethered and as promiscuous as they want.