Discernment

No matter how hard we try, we will never be one hundred percent sure of our decisions. But we have to make them. That is why discernment is necessary.
To discern is to wait, to pray, to read through events, to let go of fears and prejudices, to purify oneself from selfish agenda ...
After much prayer and reflection, at the end of the period of discernment, you don't hear a voice or see a writing on the wall that says "this is the course of action you must follow".
So you are left with trust, that after this discernment, regardless of whether your decision turns out right or wrong, since you have tried to arrive at it in truth with openness, sincerity and courage, God, who has always been with you will not leave you alone.