That is a very good question. If the direction really is from God, you will have peace in your heart. About 40 years ago, I strung some Bible verses together to justify a desire that I had. It was not a wrong desire in itself, but it was not God's will. I suffered 6 months of insomnia. I gained relief the moment I admitted that I was wrong. I had all kinds of "signs" that before, I was on the right track, but my mind was never still. Even worse, I knew better. I knew the word in Colossians 3:15, "Let the peace of Christ rule in your hearts..........." Darby uses the word "preside". Peace should be the normal experience of the Christian.
Also check your heart to see if you can let go of the promise. If we cling to something to the point where we cannot give it up, it indicates a bondage, not the liberty of a saint. Abraham was willing to give up even the result of God's promise. We are not Abraham, but God's principles do not change.