72 Once moral certainty has been obtained that the maturity of the candidate is sufficiently guaranteed, he will be in a position to take on himself the heavy and sweet burden of priestly chastity as a total gift of himself to the Lord and to His Church. In this way, the obligation of celibacy, which the Church makes a condition of Holy Orders, is accepted by the candidate through the influence of divine grace and with full reflection and liberty, and, as is evident, not without the wise and prudent advice of competent spiritual directors who are concerned not to impose the choice, but rather to dispose the candidate to make it more consciously. Hence, in that solemn moment when the candidate will decide once and for his whole life, he will not feel the weight of an imposition from outside, but rather the interior joy that accompanies a choice made for the love of Christ.
Source: Sacerdotalis Caelibatus (Vatican.va)