Speak in love and speak the truth. It is better to learn to discuss differences in a win-win framework. Sometimes a mature Protestant Christian can help guide you. There are times when God leads us to BE a witness rather than verbalize or preach. In fact, who we are and how we act should line up with what we speak.
Actions usually speak louder than words.
Different people receive love in different ways. Learn to be aware of how the other person accepts and gives love. We need to be completely yielded to the Holy Spirit in order to speak life to ourselves and others. I trust God will continue the good work He has begun in you. If you aren't ready to accept Jesus Christ as Savior and Lord, I trust God will reveal His love to you, The Greatest Love of all.