Knowing how a Gemini feels about you can be as easy as analyzing what happens when you disagree on something. Next time it happens, consider which reaction of the following three is closest to how your Gemini acts and you will know if they love, like, or just lust after you.
Love: Their eyes light up as they engage in a conversation about both your opinions. They might challenge you a bit, but they remain respectful. They light up even more if you get feisty in defense of your views but also ask more about theirs.
Like: They laugh (kindly) as you explain your point of view. They sweetly tease you about it. But ultimately, they assert why they are right and... better luck next time, hon!
Lust: They seem to get kind of mad but before it gets too heated, the conversation ends (because they move in to make out with you!).