That is Paul's concern. Guidance comes from the Bible, prayerfully used. Circumstances affecting a decision must be evaluated with the biblical parameters, and the conclusions of such evaluations must be stated in biblical terms. The advice of others is to be sought, not for their opinions but for their assistance in using the Bible to help you make a decision that honors God. Your reason is not to be trusted and must always be subjected to the Bible at every point.
Peace has no relevance whatsoever to the matter.
Questions about other aspects of guidance, especially concerning the application of general principles to particular cases, cannot be discussed here. The Bible is the source of revelation from God and the only sure guide to pleasing God.