I offer done-for-you tech service: the creation of an evergreen system to turn established coaches’ live launches into an evergreen system. (AKA automated sales system & delivery of their program)

In my offer, I create the end-to-end system (all the tech and deliver email copywriting for the email automation).

I request that my clients come with their successful offer (AKA they sell it through live launches successfully) but want to automate and this is why they come to me to create an evergreen system.

What kind of guarantee could I propose?

I’d love to guarantee sales, but I have no control over their offers. The number of sales will also be directly correlated to the number of people they will send to their evergreen funnel and I have no control over this either.

I do have an option to set a Facebook ad campaign to generate them leads so here I could guarantee leads, but this is an option only, and even if they have leads coming in, as I don’t have control over the offer I am not comfortable guaranteeing sales.

Knowing this, what kind of guarantee could I create? Knowing that what I control is that the system/tech will be created and functioning correctly. But it feels like it’s not a strong enough guarantee (not compelling enough).