We understand that you are seeking favor from God and men, particularly regarding a business venture. You've mentioned that a man approved your business plan and promised to assist with funds, but has not followed through for over three months. You've asked for prayer so that God would touch this man's heart and move him to assist you as he promised.
Firstly, we commend you for bringing this matter to God in prayer, and we are here for you. It's important to remember that God works in His own time and in His own ways.
In Matthew 6:33 But seek first God's kingdom, and his righteousness; and all these things will be given to you as well.
As we pray for God's intervention, we should also remember that God's will and timing are perfect. God may be teaching you patience and perseverance through this situation.
Also, we should not put our trust in man. Just because someone has promised something does not mean that we should wait on it to begin our dreams. This man has no obligation to provide these funds. It is much better to hope for the best and plan for the worst rather than to just wait for others to do what is best for us. We should also consider that we should not be unequally yoked with unbelievers.
WEB 2 Corinthians 6:14 Don't be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness?
This includes business. Rather than to hope for this assistance, which may not be honoring God or his word, we should be praying for God to open doors and provide ourselves.
We also pray for open doors and provision for God's will. Also, we should pray for wisdom and guidance on how to move forward. We should pray for God's will in our lives rather than our desires.
WEB James 1:5 But if any of you lacks wisdom, let him ask of God, who gives to all liberally and without reproach; and it will be given to him.
Also, we need to pray for this man. It could very well be that he is suffering from some sort of hardship or emergency. We should pray for both him and ourselves so that God can be glorified.
Also, we should be working for the funds ourselves. In the parable of the talents, the man with one talent was chastised for expecting his master to do everything for him. We need to be doing everything that we can be sure that we are doing God's will.
Let us pray:
Heavenly Father, we come before You in the mighty name of Jesus Christ, acknowledging Your sovereignty over all things. We lift up our ### who is waiting for a business venture to begin. Lord, we pray for Your will to be done. If you will that this man provide the funds, then we pray that You touch his heart and move him to fulfill his promise. And if it is not Your will, we pray for wisdom and guidance. We ask that you would open doors and provide the funds needed for Your will to be done. Please teach her patience, perseverance, and trust in You. And we pray for this man, that You would bless him and meet his needs as well. We ask all these things in Jesus Christ name. Amen
In the mean time, be anxious for nothing.
WEB Philippians 4:6 In nothing be anxious, but in everything, by prayer and petition with thanksgiving, let your requests be made known to God.
God Bless.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
