Does this make me a horrible person? How do I make amends?

Since today is April Fools Day, I decided to pull a "fool proof" prank. I decided that I would ask out one of my guy friends and while they were contemplating how to say no, I would say, "April Fools!" At lunch, I had found my victim (let's call him John). I went up to his table where he was sitting, and said, "John, would you like to go on a date with me?" He stood up with bright eyes and cheerfully shouted, "I would love to go out with you!" I stood there for a few seconds with a look of horror on my face and my jaw dropped, saying, "Uhhh..." He realized that and started to look sad. He quietly said, "This... This is an April Fools joke, isn't it?" I nodded slowly and walked away. Later that day, I found him and told him I was sorry and asked him if he was serious about saying yes. Unfortunately, he was. Then, he texted my sister and told her that I was a butt (literally, he said, "Leila's a butt."). I actually do like him more than a friend, so my sister texted, asking him to come over to hang out. He said that it was bull crap and that I shouldn't do that out of pity. How do I convince him it's not pity? PS please don't make me feel worse than I already do.