There is simply so much reason to believe the good news of Jesus Christ in history, in Scripture, as well as in our own experience that it would take a leap of faith not to believe in the gospel.
It's fine to deal with people's doubts and explain why they have good reasons to believe in Christ. But until we tell them the good news of Jesus Christ, we haven't done our job. They need a saviour that God has provided them in Christ. Once they know that, we can do as much apologetics as we need to.
Advice on evangelism needs to be tailored to individual situations. For instance, I know someone who needs to be encouraged to speak less and work more. That would be a better testimony for him because he has certainly let his work colleagues know about Jesus. It's not that I don't want him to witness about Jesus, but I have a lot of sympathy for his employer. He is paying for work to be done.
