What would most likely grab emails from this audiance?

Either A) look at what your competition is doing or B) test it out yourself.

You have to enter into the mind of the core prospect. What are they thinking about? What do they want to know? Do they really want a general book about Christianity? Maybe. More likely they have real world questions about their faith, or training in evangelism, or whatever else you can answer. Figure out what they want to know and give it to them. Then you will get sign-ups.

For example, here are some rough ideas on evangelism:

Failures Make You Learn Evangelism Better Only If You Understand These 8 Things
Here Are 8 Ways To Learn Evangelism Better
Here Are 8 Ways To Learn Evangelism Faster
Here Are 8 Ways To Learn Evangelism
Imagine You Learn Evangelism Like An Expert. Follow These 8 Steps To Get There
These 8 Hacks Will Make You Learn Evangelism Like A Pro
8 Critical Skills To Learn Evangelism Remarkably Well
8 Easy Ways To Learn Evangelism Without Even Thinking About It
8 Easy Ways To Learn Evangelism
8 Enticing Tips To Learn Evangelism Like Nobody Else
8 Even Better Ways To Learn Evangelism Without Questioning Yourself
8 Horrible Mistakes To Avoid When You Learn Evangelism
8 Incredibly Easy Ways To Learn Evangelism Better While Spending Less
8 Little Known Ways To Learn Evangelism
8 New Age Ways To Learn Evangelism
8 Powerful Tips To Help You Learn Evangelism Better
8 Reasons To Learn Evangelism
8 Reasons Why You Can’t Learn Evangelism Without Social Media
8 Ridiculously Simple Ways To Improve The Way You Learn Evangelism
8 Steps To Learn Evangelism 10 Times Better Than Before
8 Steps To Learn Evangelism
8 Surprisingly Effective Ways To Learn Evangelism
8 Things You Must Know To Learn Evangelism
8 Tools You Must Have To Learn Evangelism
8 Ways To Learn Evangelism In 60 Minutes
8 Ways To Learn Evangelism In 8 Days
8 Ways You Can Learn Evangelism So It Makes A Dent In The Universe
8 Ways You Can Learn Evangelism Without Investing Too Much Of Your Time

For once, we'd need to NOT consider the end user for a second -- and focus on your overall strategy here.

What would be the point of gathering their emails?

To just inspire people about their faith?

Or to make money?

If it's the latter, Mr. Unlimited Bear, 4.) would have to be the clear winner.

Inspiring your audience about their faith and making money are not exclusive. It depends on your particular audience. What do THEY want? Start with your audience and find out what they want most of all. They may not want to be inspired at all. You have to find out. You can do that by asking them directly, or testing different appeals until you the sweet spot.

Christians are looking for ways to become better christians, play on that and they will be signing up left right and center....Or guilt them into it:

You may be sinning without even knowing. Sign up now to find out.
7 ways you might be breaking the faith. Sign up now to find out.
You wont believe how easy evangelism is. Sign up now
Stop praying and start believing. sign up now to find out how
Christianity in a nutshell. Sign up now
The secrets to Christianity
Evangelism secrets. Sign up now
7 Easy ways to learn the bible
The easy way to become a better christian
How is everyone else being good christian
How is everyone else keeping the faith?


I clearly haven't done any research on the subject at all but its not too hard to get people to sign up when you stir their curiosity.