Taking personal accountability
It's a given customers feel more secure agreeing to do business with a salesperson who has their best interests at heart.
Source: Sales author Richard M. Schroder
One of the most effective ways to convey that sentiment is by taking personal accountability for ensuring all issues are resolved quickly, and – more importantly – the customer is satisfied with the outcome.
It might even be helpful to let prospects know during the initial selling process that you're always available to answer any questions they have. This way, the two of you are in sync every step of the way, which ensures you'll be the first to know when or if any issue does arise.
More importantly, it allows salespeople to transform the occasional service issue into an opportunity to build trust, increase loyalty, and, ultimately, create the type of customer relationships great businesses are built upon.