Scholars of hadith in the field of rijal study several points to determine whether a hadith is authentic or not. First and foremost is the truthfulness of a narrator. The faith and truthfulness determines the reliability.
Scholars of hadith say that as long the narrator is reliable, it is okay if there is some variance in the wording. Scholars acknowledge that some of the narrators have recorded narrations in meaning not in wording, and as long as the narrator is deemed reliable the hadith is accepted.