Which suffix means “suitable for”? -ful -ure -al -ize

-al

Explanation:

The suffix "-al" is often used to pass along the idea of "Like" or "Suitable for".

You can see that in words like: Spacial, which is most likely "Suitable for Space" (Spacial Awareness, for example) and Optional, which is something that "fits an Option" (as in, something that will not be mandatory).

the characters in string all have major secrets that they strive to avoid revealing throughout the play.