You should try not to use such terms… it can come across a bit like “billy no mates”. Something like what duke said " hey I had a great time, we should do it again soon". You could also add in " will check my calendar to see when I will be available", this points out that you have much more going on in life than sitting waiting around to be txed. Men love a chase, sometimes the harder the catch the more interest generated.
The best thing you could do is focus on improving yourself, keep up the training, go out with friends, get your hair done, just enjoy being single and independent. Somewhere down the line out of the blue something will happen. If he had more interest he would be instigating things a lot more, thinking about you often and txing, clearly he has other things going on that are higher priority than you. I know if I fancied a girl and I was interested, she would be constantly on my mind and I would be making it a priority to make sure she knew.