If you are going to validate WooCommerce emails, You have two options:
Option 1: Using the WordPress Plugin
Protect Your Sender Reputation with Instant Email Verification
The DeBounce WordPress Plugin helps you build a reputable list that is free of spam and invalid emails. Prevent email-entry mistakes to increase open rates, save on your marketing budget and protect your sender reputation. It’s time to take charge of your list! This plugin works perfectly in WP registration forms and integrates with most form builders.
Next, you need to add your domain URL into the approved domains list. This is a security factor that only enables the widget on your specific domain. Click on "CORS Domains" and add your website address. Please note that the CORS URL must follow these rules: 1) It is not sensitive to http and https; 2) It is sensitive to www and non-www; 3) If your webpage is on a subdomain, you must add the subdomain too; 4) You must enter the root URL of your webpage. Some possible examples: example.com, my.example.com, www.example.com.
Add your public API key into the following code. The integration code is now ready. You just need to add it to your checkout page.
All you need to do is add the code with which you have been provided into your WooCommerce checkout page. Here is a blog post that helps you do just that. That's all. The emails filed must now be integrated into DeBounce email validation engine.