She be at home by now but it's not sure at all.

Could

Explanation:

 The modal verb could  correctly completes the sentence "She could be at home by now but it's not sure at all." This verb can be used for situations when it is expressed a possibility, specially slight or uncertain possibility. Could be can be used instead of may/might be. She may/ might/could be at home (perhaps she is at home).

the statement flat characters usually only have one trait that is developed in their story lines is true.

- "the die is cast; i have consented to return if we are not destroyed. thus are my hopes blasted by cowardice and indecision; i come back ignorant and disappointed. it requires more philosophy than i possess to bear this injustice with patience. i have lost my hopes of utility and glory; i have lost my friend."