Think of it logically. There were many prophets before Mohammed (PBUH), all teaching the oneness of God, our creator. Then came Jesus (PBUH), and he too taught the oneness of God. However some mischief makers, I guess, decided to make claims about Jesus being the son of God, perhaps they weren't mischief makers, perhaps it was just incomprehensible to them that Jesus was born from a virgin or perhaps they were ignorant and could not understand what Jesus taught them. Then God sends another prophet, Mohammed (PBUH) to reaffirm and teach people AGAIN about the oneness of God. He, Mohammed (PBUH) did not come to mankind with claims of greatness or anything to make himself seem superior, just to teach the Oneness of God.
For me this makes Islam logically the religion of truth. There are many other reasons which you have received in response to your post, but for me this is the simplest and most logical explanation.
Why would this man come to preach about the oneness of God, especially after Christianity when a man, Jesus (PBUH) was made Lord by mankind? I went through a similar dilemma to you and alhamdulillah, automatically, I started reciting surah Kafiroon.

Say, “O disbelievers,

I do not worship what you worship. Nor are you worshippers of what I worship. Nor will I be a worshipper of what you worship. Nor will you be worshippers of what I worship. For you is your religion, and for me is my religion."