Can God tell you not to marry the person whom you are dating without a reason?

Answer:

Underlying this question is an assumption that God directly communicates with people today. But that very assumption contradicts what God said He is doing. See: God is Speaking to You and Does God Speak Directly to Mankind Today?

God has given you instruction through His holy book regarding how to pick a proper mate. His book contains everything pertaining to life and godliness (II Peter 1:3). If you follow His guidance, you will likely find a suitable spouse. You should pray for help and wisdom as you make your choice. You should read all you can about marriage from the Bible. And then you must trust God as you move forward with your choice.

People who claim to receive revelations from God are nothing more than frauds. They use the belief people have in them to control people's lives.

You ought to get advice from trusted people who can help you examine whether you are seeing everything you ought to see. Often we get so excited about finding a potential spouse that we overlook problem areas. Having the advice of others makes sure we think about solutions to those problems. "Where there is no counsel, the people fall; but in the multitude of counselors there is safety" (Proverbs 11:14). Still, the ultimate decision is your own.