It’s wonderful that you are a Christian and it’s wonderful that you want to tell people about Jesus. I hope it will bring you comfort to know that I have been a Christian for over 20 years and at times still find it hard to talk to people about Jesus! There are so many things that go through our heads, like, ‘Will I say something really dumb?’, ‘Will I lose this friendship?’, ‘Will they think I’m deluded?’, ‘Will I say something that is actually unhelpful in bringing this person closer to God?’. You may have a whole lot of other thoughts that go through your mind.
The first thing to understand is that the bible teaches us in Ephesians 4:11-12 that God gives the members of Christ’s body different gifts, including evangelism. It is possible that evangelism is not your particular gift (though I don’t want to discourage you if you find your confidence grows in time). However, in 1 Peter 3:15 we are all called on to"set apart Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect”“
We often forget, but need to remember, that sharing the gospel is God’s work, and he has given us the privilege of being a part of it. Because of this, the first step in sharing Jesus is always prayer and lots of it. We can pray for particular people, we can pray for opportunities, we can pray for the right words to say, we can pray for courage, we can pray that what we do and say gives honour to God, and that our lives are a light in the world to those around us. We need to remember God’s sovereignty, knowing that whatever mistakes we might make, God’s plans will not be thwarted. God may also cause us to grow through our mistakes too. God uses the foolish, weak and lowly (1Cor 1:27) to bring about his purposes. It’s ok to say that we don’t know something, but will look into it, if given a tricky question. We may well only be ‘a link in the chain’ of bringing a particular person to Christ, so we don’t need to feel that we have to get the entire gospel out or cover everything in one conversation. I found this concept really liberating, because now I know that God can use even the slightest comments to get people thinking even when we are not aware of it and may never be, in this life. I found ‘Promoting the Gospel’ by John Dickson really encouraging. He covers the various aspects of our lives that go into promoting the gospel, not just our words.
Often we have confidence to say what we believe when we are sure in ourselves what it is that we actually believe in and why. It might be helpful for you to get the answers to these questions clear in your own mind, and then you may find you have greater confidence in talking with your non-Christian friends. The Bible is, of course, the place to start. In Romans 1:16 Paul says that he is “not ashamed of the gospel, because it is the power of God for the salvation of everyone who believes.” The gospel is given in a nutshell in various verses, but John 3:16 is a classic-“For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.” Kel Richards’ book ‘Defending the Gospel’ may also be really helpful to you in this.
Knowing how others think, their world view or their objections to Christianity, where the inconsistencies in their thinking lie or the false assumptions they may be making, can all be really helpful in knowing what is best to say to reach them. This would definitely be an ongoing gaining in knowledge (we can’t expect to know everything at once!), but if you are into reading there are many great books that can give you head start. I thoroughly recommend ‘The Universe Next Door’ by James Sire and ‘A spectator’s Guide to World Views’ edited by Simon Smart which look into world views. Also, ‘How Long O Lord?’ by D.A.Carson looks into the common objection about suffering and evil and ‘The Christ Files’ by John Dickson looks into the common objection about the historical reliability of the gospel accounts of Jesus.
I hope and pray that this helps you Wendy, and that as you grow in the clarity of your understanding you will find it easier to speak up for Jesus.