"As a man thinketh in his heart, so is he."
Giving your heart to another is one of the greatest gifts you can give. If given without much thought, it can also be a painful experience. Knowing with whom to share is an essential lesson of love to learn.
Take time in the beginning to discover more about him. Doing so can mean the difference between falling in love with a man who will carefully and responsibly tend to that love and one who will take it for granted, or exploit what you have given him. While you can't determine with complete certainty whether someone will ultimately hurt you or not, you can move slowly, learning more about the person before becoming deeply involved.
The early stage of a relationship is a time to begin sharing your history and current life experiences with one another. You will each say a lot, but evaluate beyond the words. Witness the other person's actions in various settings, body language in conversations, and contemplate deeper what is being shared. By focusing on these things, you can learn whether a person's nature includes being honest, caring, faithful, loving, supportive, responsible, and more.
If you are able to see what is in his heart, you will discover his essence.
Only then should you give your own.