Why does he act like he likes me yet cancels constantly?

When we are together it’s so natural, good rapport, great chemistry. He truly seems super into me. But he’s cancelled five times, the last time was because he was “too tired.” He used to text back instantly, now it takes hours. He doesn’t really engage in the conversation anymore the way he used to. It seems obvious from his actions he doesn’t like me. But why does he make it seem like he does when we were together? Why not just say I’m not that into you?