This is a trustworthy statement; and concerning these things I want you to speak confidently, so that those who have believed God will be careful to engage in good deeds. These things are good and profitable for men. (Titus 3:8)
Paul wants Titus to understand that all that has been said, has been the Gospel as was entrusted (Titus 1:3) to Paul to deliver.
Because it is a faithful explanation of God’s plan of salvation, Titus and others are to have confidence in the message when they deliver it. Note that it is not an if, but an assumption that the Gospel message will be repeated.
The message as delivered is to drive those that believe to good deeds. Sanctification is the process of becoming “set apart”.
Discussions surrounding the topics previously mentioned in the letter are profitable to men. Discussions of these topics have value in the Christian walk.