How can a Christian woman help her husband to become a Christian?

You must pray for him, read the Bible with him, speak very gently to him, obey and honour him. But much more: be an example of what a true Christian is, so that he is not tempted to doubt the value of being a Christian. Do not preach to him. Read 1 Peter 3:1-6. By living according to the Bible, you will bring him to God without saying a word!