I am working and my wife is also working. Since we got married we have never kept our money separate, and she is a full partner. We have bought land and built a house for ourselves on it. 
The land was put in my name and the house was put in my name as well after that, although her share in the house and the land is approximately one third. 
Because that is an agreement between me and her only, I hope that you can advise me of the best shar’i way to prove her share of ownership in the property (one third). Is it legally possible to make what is in the title deed shared between me and her according to the rate that I mentioned (one third versus two thirds)? 
Please note that we have three boys and one girl, and my wife is not asking me for anything right now; rather I am asking this of my own accord so that I will not be held accountable in the Hereafter.

Answer

Praise be to Allah.
So long as you have agreed that she should have a share in the property commensurate with what she has spent, which is one third, then that should be recorded and proven by means of official documents, so as to protect everyone’s rights. 
Based on that, what is mentioned in the title deed should be shared between you and your wife according to the rates that you have mentioned, so that you will have two thirds and she will have one third. 
The Scholars of the Standing Committee for issuing Fatwas were asked: 
I am an old man. Previously I bought a piece of land for 85,000 riyals. I have two sons, and my sons and I developed it equally, paying equal amounts for development. I paid 217,000 riyals and they paid together 175,000 riyals. My question is: is it permissible for me to write that they have a half share for the money that they paid? Please note that I agree to that and that I have daughters besides them. 
They replied: 
If the matter is as described, then there is nothing wrong with recording the building as being shared between you and your sons, and that they are partners with you commensurate with the money that they paid to you, and the money they paid was not a donation or gift to you. End quote. 
Fataawa al-Lajnah al-Daa’imah, 14/303-304 
Shaykh Saalih al-Fawzaan (may Allah preserve him) was asked: 
We are seven siblings, four females and three males. Allah has blessed us by enabling us to buy a piece of farmland. We put together all that we own, we even took the women’s jewellery, and paid it for the land. Because we were very keen to please our father, we registered half of this land in his name, but now he has died. We did not give our sisters any part of it and they have not asked for anything, because they know about the circumstances of its purchase and our living circumstances. We have not given anything to our wives either, and they accepted that willingly. What is your opinion concerning my sisters first of all? And also concerning our wives — do they have any right to that or not? 
He replied: 
With regard to your sisters, if when you registered half of the land in your father’s name, it meant that you gave him this half, then in that case it is part of his estate which is to be inherited from him by his children, both male and female, and other heirs who have a right to the shares of inheritance prescribed by Allah, so it becomes an estate which is to be divided among his heirs, and his heirs include your sisters. So they should have their share of this land according to the rules of inheritance, from their father’s share. 
With regard to your wives, if they also took part with you in purchasing it and they gave the jewellery on the grounds that they would be partners with you in buying it, then they are entitled to a share of this land. But if they gave this jewellery to you in the form of a gift to you to help you to buy it, then it belongs only to you. End quote. 
Al-Muntaqa min Fataawa al-Fawzaan, 2/54.