To dream of a necklace represents a total commitment to an decision, idea, situation, or other person. There is a commitment with both mind and action.
If someone doesn’t want to put on a necklace it represents unfulfilled desires, resistance, or rejection you are feeling in life.
Negatively, dreaming about may reflect big commitments that are irrational or that are towards people who don’t feel that same way about you as you do about them.
Example: A man dreamed of trying to put a gift around the neck of a woman he fell in love with and watching her think it was weird. In waking life he had fallen in completely in love with this woman and later found out that she wasn’t interested in him at all.