Assuming he is a man of principles, avoiding to commit is a bad sign (would he be a lying and deceiving man it would of course be worse). Without a collar it is hard to believe in sincerity and long/ term engagement. In “in-between” it is hard to be a good sub/slave. Show your Dom/Master/Owner that you need more and long-term, observe reactions. At some point you will need to realize that if He does not commit, you need to move on. A good Master must show/tell/guarantee He is in for the long term.