If set to 0 then commissions will be calculated instantly.
If you set it to -say- 30 days, then commissions will be credited to affiliates' accounts (for this SPECIFIC PRODUCT) after 30 days.
If a customer requests a refund during the period specified here, you can click "Sales," find the order and mark is as refunded. JVM will NOT credit the orders you have marked as refunded. This can be done ONLY during the period (in days) you'll specify in this field.
By default, JVManager will apply the guarantee period to recurring sales too. So if you have -say- a subscription that bills the customer every 30 days, and define a Guarantee of 30 days here, then JVManager will release the commissions (if any) after 30 says. If you check the "Do not apply guarantee period for recurring sales" box then JVManager will release the commissions of the first (initial) sale after 30 days and then will release the commissions for the next recurring sales on the date the customer is charged.Note: if you choose NOT to apply the Guarantee on recurring sales in a subscription of 30 days with a Guarantee period of 30 days, then the first and the second commissions will occur on the same day.
You can change the Guarantee period for an existing Sale through the Sale's individual record.