Remember when you are conversing with people, the primary thing they will try to do is protect themselves. Therefore, they will not agree with your idea or decision unless they feel it is beneficial to them to agree. They need to feel that agreeing with you either reduces their pain or gives them greater gain. So if you want them to agree with your idea, you have to speak from their perspective and not yours. You need to figure out why they would agree with your idea and then focus your conversation on those points of agreement. Remember, most people are incentivized more to flee from pain than they are to flee toward gain. Therefore, it is in your best interest to show how your idea will help remove a problem or issue they face.
If you want people to move towards a decision, you need to think about the advantages to them to make that decision. If this person is concerned about stability, you should talk about how making the decision will give them stability. If a person is concerned about recognition or reputation, you talk about how making the decision will set them apart in the marketplace. If the person is concerned about control, you want to show how making the decision will give them greater control. If the person is concerned about accuracy, you want to show how making the decision will allow them to be more precise and move forward.
Stop trying to move the person toward you but instead look at what you need to do to move closer toward them.