Ascertain - When you ascertain a fact, be as certain as you can.

Because - Big Elephants Can Always Understand Small Elephants

Believe - When someone lies, they hope you'll believe them (believe)

Bookkeeper - Three double letters in a row

Cemetery
- Three Es are buried in the cemetery
- Walk past the cemetery and screen 'Eee!'

Friend - You wouldn't want a fiend for a friend, remember how you r.

Hear - You hear with your ear (hear)

ie -
I before E except after C
Or when saying "A" as in Neighbor or Weigh
And weird is weird.