A: What would I say? I would begin by cautioning against giving in to irrational fears and anything that could be exploited by the enemy. Next, I would encourage a deeper understanding of God's Word that would supplant the places where this kind of fear might choose to dwell.
The idea that a person can pray themselves out of the will of God is a diabolical thought that is sure to steal both the pleasure and the intimacy of prayer. God wants you and I to come to Him and pour out our hearts, and you can be sure when you do, there will be times when you speak things in prayer that are not in the perfect will of God. We all do this. It's part of being an imperfect creature who sees "in a mirror dimly." But Jesus modeled for us the perfect prayer for any such request that may miss the mark of God's will. This is recorded for us in Matthew chapter 26 where it says...
And going a little farther he fell on his face and prayed, saying, “My Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will.” Matthew 26:39 (ESV)
Did you notice how Jesus amended His request? "...not as I will, but as you will.”
This is the attitude in prayer that God would have us bring into all our petitions. Jesus included this instruction also in The Lord's Prayer, when He told us to say, "Your kingdom come, your will be done on earth as it is in heaven." (Matthew 6:10)
We don't pray this way out of a fear that anything less will override the will of God in our lives, but rather we say it out of an attitude of submission that always desires to quickly and humbly kneel before the sovereign wisdom of our heavenly Father. This is the attitude that Jesus always modeled for us. This is outlined for us in the book of Hebrews where is says...
During the days of Jesus' life on earth, he offered up prayers and petitions with loud cries and tears to the one who could save him from death, and he was heard because of his reverent submission. Hebrews 5:7 (NIV)
Why were the prayers of Jesus heard? "...because of his reverent submission." Jesus wanted the will of God the Father above all else. However, that desire never kept Him from praying.
Don't ever let fear keep you from the place of prayer. Come before Him with confidence and lay your petitions before Him as you would a loving Father who knows what you need even before you ask Him. And know this also, that God has promised to lead you according to His will and He will not go back on that promise.
I will instruct you and teach you in the way you should go; I will counsel you with my eye upon you. Psalm 32:8 (ESV)
So when you pray, add the word of submission to all your requests, asking that God's will would sovereignly trump your own should you ever seek anything contrary to His plan.
God bless you!
And this is the confidence that we have toward him, that if we ask anything according to his will he hears us. 1 John 5:14 (ESV)