A water route to Asia, in the past, would have made trading much easier and much more profitable instead of having to traverse hazardous countries, pay tolls to use roads, hazardous deserts, like the Gobi Desert. A water route was also going to prove much quicker than a land route.
So the reasons were speed, safety, and money.
Spain hoped they would become wealthy from Spain if (Columbus found a way to Asia).
because it was a faster way to travel for trading
Like all explorers of his time he wanted to find a water route to Asia.
He was looking for a water route to Asia.
prince Henry believed that if explorers found a way around Africa then that would be a short cut to Asia.
Spain
They were looking for a water route to Asia and wanted one across North America. The Silk Road was dangerous, expensive, and took too long to get things to Europe.
He was looking for a water route to Asia. The Silk Road was long, dangerous, and expensive so water route would be faster and get more things to Europe.
They wanted to find a direct water route to Asia, for trade.
so he could get there faster
to find a western trade route to Asia
C
He ( and others) were looking for a faster sea route to Asia. The overland trade routes were slow and dangerous so it was thought that a water route to Asia would be better. He was also after riches and fame.
They wanted to find a water route to Asia because it was a faster and easier way to travel there than by land and water. Asia had many products such as silk and spices which would make you rich if you traded for it and then sold it in Europe.