What is your best advice for using a double opt-in process when capturing an email address on page 1 of a web form application?

My company's current product/service is one that requires an application to be submitted. So we capture email addresses on page 1 of this application. What we've seen is that many people submit dummy/fake email addresses when prompted, so I'd like to transition to a double opt-in process. The issue with this is it would negatively impact the user experience of the application process and would slow it down (one of our value props is a fast, easy application), so I am aiming to determine how to successfully only capture valid email addresses while also not negatively impacting the application process.

Any suggestions?