What guarantee does St. Clare ask of Haley in regard

I will need a chapter for this question, and also please inform me what the guarantee concerns. In regard to? 

Jill d chapter 14-16

Haley guaranteed that Tom wouldn't run off because of his strong character and sense of morality. 

"Wal, there might be something in that ar, if it warnt for his character; but I can show recommends from his master and others, to prove he is one of your real pious,—the most humble, prayin, pious crittur ye ever did see. Why, he's been called a preacher in them parts he came from."