Why Did King Ferdinand And Queen Isabella Send Christopher Columbus To Explore America?

They didnt isabella rejected him im doing research on her

They didn't send him to explore America. They gave him ships to discover a new passage to the Indies. The Indies trade route was very important because of spices, silks, china and exotic woods. The traditional route was very long, going South and West circumnavigating Africa and the Indian sub-continent. C. Colombo believed that since the earth was round he could travel East and reach the Indies in a much shorter time.
He "stumbled" upon what is now know as the American continent by chance.

Queen Isabella rejected Christopher Columbus's plan to reach the Indies
by sailing west more than three times before changing her mind. It
actually took her about 1-2 years to agree to his plan. His conditions
(the position of Admiral; governorship for him and his descendants of
lands to be discovered; and ten percent of the profits) were met.
On August 3^rd 1492 his expedition departed and arrived in
America on October 12. He returned the next year and presented his
findings to the monarchs, bringing natives and gold under a hero's
welcome. Spain entered a Golden Age of exploration and colonization. In 1494, by the Treaty of Tordesillas, Isabella and Ferdinand agreed to divide the Earth, outside of Europe, with king John II of Portugal.