How may syllables does hero have?

The noun "hero" has two (2) syllables: he-ro.

Here is a primitive but useful way to determine the amount of syllables in a Word:

Place the back of your hand on the bottom of your chin (on your jaw). Slowly mouth the Word and count how many times your move your mouth up and down.

For an example, place your hand in the specified location and say the Word "time". Your jaw goes down one time, so the Word "time" has one syllable.

Now say the Word "tenacious". Ten-a-cious equals three syllables.