“يَصْلَ” (yaṣla)means “They will burn (in) it” in this verse. It is a verb. an action or state word. Here it is imperfect verb, third person — masculine — plural.Corpus grammarV — third person masculine plural imperfect verb.
“وْنَ” (wna)an attached pronoun meaning “they” or “them.”Corpus grammarPRON — third person masculine plural subject pronoun.
“هَا” (hā)an attached pronoun meaning “she” or “her.”Corpus grammarPRON — third person feminine singular attached pronoun.