Double-Opt-In for Contact form

Hello,

I am facing the problem the problem, that due to data private policy we need to have a Double-Opt-In process for the contact form on our website.
With the normal contact form from the enfold template I did not figure out an easy way to implement this.
Is there some way to do it with this, I oversaw or do I need to use another plugin?
If yes, do you have any recommendations which one to use?

Thank you,
Gerke