Evangelization is typically described as the preaching and teaching of the Gospel to the whole world.
While preaching the truth is certainly an essential part of evangelization, one could argue it is "secondary." What is primary in evangelization is living an authentic witness of the Gospel.
St. Paul VI expertly laid this out in his apostolic exhortation, Evangelii Nuntiandi.
Being a witness to the Gospel is such an important part of evangelization. It shows to the world that we practice what we preach.
When we preach charity, they first see it by our actions.
When others hear our words, but do not see it reflected in our actions, they disregard everything we say. The truth, when it is not lived out fully, has little effect on the hearts of the people.
St. Paul VI pointed this out as well.
We must preach the truth in the Gospel, but that preaching or teaching will fall on deaf ears if it is not first found in our way of life.