Well, not just because Christians worship the true God, but because Christians by definition believe in Jesus.
Like this
Acts 2: 38 Peter said to them, "Repent, and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of sins, and you will receive the gift of the Holy Spirit. 39 For the promise is to you, and to your children, and to all who are far off, even as many as the Lord our God will call to himself."