1. The 1/3rd sharer who is not settling cannot be forced to sell his share or buy the shares of the other two
2. It appears that the court has declared that the 3 persons claiming share are the legal heirs and thus entitled to 1/3 share each. The arrangement of any sharer either selling his share to a stranger or to the other two or buying shares of the other two, is only suggestive in nature.
3. What is the reason why the 3rd sharer is refusing to settle? Have the other two sharers approached hin to either sell his share to them or buy off his share from him? Have you tried to figure out his apprehension for not settling?
4. Also what kind of property is it? Is it a flat or some land?
5. You will need to file an execution petition for executing the court decree
6. Normal courts fees will be charged for above petition
7. In case the property is a land, the other two sharers won't find difficultly in selling their respective undivided shares
8. If property is a flat then obviously no one would want to buy only a portion of undivided share in the flat. In such a case the buyer won't be able to use the flat for residing and it can only be held as an investment. In such a case there would either be no buyer or the price offered to buy only a specified share and not the full flat, will be lower
9. Generally if the sale happens through court, the court considers the market value of the property for sale. In many cases the sale price that can be fetched is higher than the market value and there is often a cash dealing involved. This cash dealing can't happen if sale is through court. So in that context the sale price that can be fetched will be lower
10. You must first figure out what is the apprehension and concern of the 3rd sharer and counsel him before proceeding to have the decree executed by court.