You know, I don't actually know. That crossed my mind while I was writing Mako's heartfelt bit about Asami and wanting to love her like she deserved. I think given Mako's attitude in the series' as a total scumbag he wouldn't have said it, but this is a Mako working to reform. I've never been in a position where I'd kiss another girl if I had one already but I think Korra was a fling. They're attracted to one another but other than that I didn't really see the chemistry. Season 1 was just so ...'okay'. 

So if Asami's hearing love now and she never heard it before, her heart must be racing like hell I imagine X.X