What is the specific purpose of the encyclical letter?(veratatis splendor)?

Question

it is written by late Pope John Paul II

Answer 1

Full text of the letter is available on the link below. He answers your question in the letter itself:

The purpose of the present Encyclical
Today, however, it seems necessary to reflect on the whole of the Church's moral teaching, with the precise goal of recalling certain fundamental truths of Catholic doctrine which, in the present circumstances, risk being distorted or denied. In fact, a new situation has come about within the Christian community itself, which has experienced the spread of numerous doubts and objections of a human and psychological, social and cultural, religious and even properly theological nature, with regard to the Church's moral teachings. It is no longer a matter of limited and occasional dissent, but of an overall and systematic calling into question of traditional moral doctrine, on the basis of certain anthropological and ethical presuppositions. At the root of these presuppositions is the more or less obvious influence of currents of thought which end by detaching human freedom from its essential and constitutive relationship to truth. Thus the traditional doctrine regarding the natural law, and the universality and the permanent validity of its precepts, is rejected; certain of the Church's moral teachings are found simply unacceptable; and the Magisterium itself is considered capable of intervening in matters of morality only in order to "exhort consciences" and to "propose values", in the light of which each individual will independently make his or her decisions and life choices.