With all due respect, you need to be very careful with this question. Actually, this novel was written and based before the policy of apartheid was introduced, so we need to remember the historical context of this amazing story. However, having said this, we can definitely see within the pages of this novel the massive social issues that resulted in the policy of apartheid and the disempowerment of all other races under the whites. Consider the disparity of wealth that is evident between the whites and blacks, and the creation of shanty towns and the atmosphere of fear that breeds freely in Johannesburg. Note the following quote, which is one of many in the novel that refers to these issues:
Have no doubt it is fear in the land. For what can men do when so many have grown lawless? Who can enjoy the lovely land, who can enjoy the seventy years, and the sun that pours down on the earth, when there is fear in the heart? Who can walk quietly in the shadow of the jacarandas, when their beauty is grown to danger? Who can lie peacefully abed, while the darkness holds some secret? What lovers can lie sweetly under the stars, when menace grows with the measure of their seclusion?
Note how this passage points towards the huge social unrest that South Africa was suffering as a result of so many issues. In spite of the optimistic ending of this novel, these issues were combatted by the policy of apartheid, which only caused the exacerbation of the racial divide that so sharply split South Africa.