The different levels of trust define the different levels between a prospect to a repeat buyer to a brand advocate.
The role of email marketing is to move a person from one level of trust to the next deeper level.
Product Recommendations can be used to move your audience at each level:
Interested -> Engagers
Engagers -> Buyers
Buyers-> Repeat Buyers
Maropost’s Product Recommendations works best for clients who’ve integrated their Marketing Cloud accounts with their ecommerce platform. But it still can be used by anyone just to jump-start it in emails.