To put it bluntly, I feel that he doesn't like you that much. If you continue to insist on not giving up, there may be a turn for the better!
But at present, what he said ("aren't you so persistent") just doesn't want to be responsible and establish a relationship.
You must make it clear.
If you are open-minded, but not so open-minded and not so easy to let go, I advise you not to take it too seriously.
Then he will pat his ass and leave, thinking that you are strong and mature and won't get hurt.
You'll be stupid then.
Emotion is also a game that needs to be evenly matched. Obviously, you can't beat him. Be careful not to get hurt.