Is Jesus really God?

Simply put: Yes.

Why? This is a little more complicated, and based upon acceptance that the New Testament is accurate and that Jesus was being truthful.

Jesus directly claimed to be God Himself - and directly said He was part of the Trinity. He used the Name 'I AM' to describe who He was, a direct allusion to saying He was God. One of the official names of God is 'I AM'.

"Jesus said to them, “Truly, truly, I say to you, before Abraham was, I am.”" John 8:58, ESV

"God said to Moses, “ I AM WHO I AM.” And he said, “Say this to the people of Israel: ‘ I AM has sent me to you.’”" Exodus 3:14, ESV

"I and the Father are one.”" John 10:30, ESV

This can be easily overlooked by modern readers because of Jesus using His 'I AM' name - although those who are closely familiar with the Old Testament/ are Jewish will immediately recognize the significance of these words Jesus spoke in John 8:58.* John 10:30 is Jesus declaring that He is part of the Trinity.

In other words Jesus is God. 

Interested in Christianity? The Gospel in a Nutshell can be a good place to start! And Church of course : )