Jesus was 'qualified' to be our Saviour because He is God and because He was sinless
Jesus Christ, the Son of God, lived on the earth as a man for about 33-34 years. He was probably born in the year 4 BC - our calendar is slightly out of line. During His life He never committed any sin whatsoever. He was entirely innocent. This was because He had a sinless nature. He had been conceived within Mary through the power of the Holy Spirit. Therefore He had not inherited the sinful nature that you and I have inherited from our first ancestor, Adam. Because Jesus had no sinful nature, and because He was also the Son of God, (at the same time as being a man), He was able to live His whole life entirely without sin.
At the end of His time on this earth, He went to Jerusalem on the very day that the prophet Daniel had prophesied. There, on what we now call Palm Sunday, He formally and publicly presented Himself to the Jewish people as Israel's long awaited Messiah. But, tragically for them, the majority of the Jewish people rejected Him. Many of them did so even though they already knew perfectly well that He really was their Messiah.
The Jewish High Priest and those around him were especially well aware that Jesus was the Messiah. They had followed Him around for three and a half years to investigate His miracles and had seen them happen right in front of them. They rejected Jesus because He criticised them and the way they put their man-made traditions ahead of what the Bible says. It was not because they thought He was a fake. They knew He was genuine.
Then, as a result of a conspiracy by some of the leading Jewish officials, working together with the Roman authorities, men contrived to have Jesus falsely accused. He was put on trial and falsely convicted. He was then unjustly sentenced by the Romans to crucifixion. This was the Roman method of execution for those who were not Roman citizens. It was a slow and very cruel way to kill somebody. The word crucifixion is where we get the word 'excruciating' from because it was so painful.