What is an example of anapestic pentameter?

Iambic*

Take any line of a Shakespeare Sonnet. For instance, 137:

"Therefore I lie with her and she with me,

And in our faults by lies we flattered be"

The first syllable is unstressed. The second is stressed. The third unstressed. Etc.

"with" does not take as much effort to say as "her".

The effect is an alternating pattern of stress/unstress which makes it feel like it flows off the tongue.