All those years hauling junk have made Rey quite strong - so strong that she can bench press Chewie without breaking a sweat. Luke finds this in combination with her sunny disposition impossibly attractive. Meanwhile Rey knows exactly what effect she's having on Luke, and subtly flexes whenever he's around just to see him sweat loudly.

+ 10 if Rey bench-presses Luke
+ 100 if they get into a situation where Rey has to wrestle an unsavory beast to rescue him.
+ 1000000 if she dips and kisses him afterwards