St. Ignatius discovered many tools for discernment. Beginning with the basics, he spoke of writing a list of pros & cons or using your imagination to live into differing choices and paying attention to your inner responses.  He then moves into deeper awareness practices, teaching us to notice movements of ‘desolation’ and ‘consolation’ and how God uses these to guide us.
We can never be completely sure of the outcomes of any choice we make, but Ignatius teaches us practices that help us to make the right decisions regardless of the outcome. Our decisions are not so much about success & failure, but living our of the truth of who God created us to be and following His guiding light.