We understand your desire for clarity in your friendship and we are here to pray and offer biblical guidance with you. Firstly, it's important to remember that God's will is always the best path for us, and He knows what is best for our lives. As it says Psalm 37:4-5 WEB, "Delight yourself also in Yahweh, and he will give you the desires of your heart. Commit your way to Yahweh. Trust also in him, and he will do this". It is good that you are seeking God's will in this situation.
However, we want to remind you of Hebrews 11:6 WEB which says "Without faith it is impossible to be well pleasing to him, for he who comes to God must believe that he exists, and that he is a rewarder of those who seek him". You need to believe in Jesus Christ as the Son of God and the only way to eternal life. It is by the name of Jesus that we have access to God.
We also want to address the nature of your relationship. You mentioned that you have been writing for years and that you love him. While love is a beautiful thing, it's important to ensure that your relationship aligns with biblical principles. If you are not married, it's crucial to maintain purity and avoid crossing boundaries that God has set for our protection. Remember what it says in Ephesians 5:3 WEB, "But sexual immorality, and all uncleanness, or covetousness, let it not even be mentioned among you, as becomes saints".
As you seek God's will for your friendship, pray that God will give you both wisdom and discernment. Here is a prayer we can offer together:
"Father in heaven, we come before You in the name of Jesus, seeking Your will for this dear sister's friendship. Lord, we ask that You open the door if this relationship is aligned with Your will, and close it if it is not. Give her the wisdom to understand Your plans and the strength to accept them. Help her to trust in You completely, knowing that You have the best in store for her. We also pray that You will bless this friendship with purity and godly love. In Jesus' name, we pray. Amen."
Remember, God's timing is perfect. Trust in Him, and He will direct your paths. As it says Proverbs 3:5-6 WEB, "Trust in Yahweh with all your heart, and don’t lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight".
If you have not already, consider studying the Bible together and praying together to build a spiritual foundation for your friendship. This can help you both grow in faith and understand God's will more clearly. May God bless you and guide you in His perfect will.