Once you set filters in the rule scope, you will see an “Estimated match” number which shows the number of ads/ ad set/ campaigns that currently match the filters of the rule. Please note that this number might change in case your ads/ ad set/ campaigns are being changed dynamically.

Here is more on how estimated match works. If you aren’t sure that you set the filters correctly, you can first create a “Notify” task with conditions you plan to have in a main rule. Set this “Notify” rule live and after the first check you will be able to analyze logs and decide if the checked items is what you need.