Assalam Alaikum
These are the reasons why I believe in Allah and why I believe Islam is the truth:
There is too much harmony, rhythm and perfection in this universe to have more than one creator. Truly I believe in only one God, the Lord, Master and Creator of the Universe. He is Allah (SWT). Allah = One God who is worthy of worship.
Islam is perfect (even though its adherents may not always be). Islam unites all races. The Qur'an has so many scientific facts (that were only 'discovered' in the recent years). That alone is evidence enough for the those of a scientific mind. Islam gives rights to women which were not given in the so called modern/secular world tilll recently.
I was born as a muslim to muslim parents. I can say with all honesty, that inspite of that, I am a muslim by choice (first and foremost by Allah's grace) because nothing else makes sense to me, but Islam. Alhamdullilah!
Assalamu Alaikum