Reading this one sentence in Arabic (which is called ‘Shahada’) will make you a Muslim now:

أَشْهَدُ أَنْ لَا إِلَٰهَ إِلَّا اللّٰه وَأَشْهَدُ أَنَّ مُحَمَّدًا رَسُولُ اللَّهِ

Say these words clearly:

Ash-Hadu An La Ilaha Illa-Allah Wa Ash-Hadu Anna Mohammadan Rasool-ul-Allah

This is how we declare our faith in Islam.

These words mean:

“I bear witness that there is no god but Allah (the Only God), and I bear witness that Muhammad (peace be upon him) is the Messenger of Allah.”

Believe this in your heart, and say it sincerely to become Muslim.