Question

how do I rewrite this sentence so it can be more clear The boss told the employee that she would receive a raise replace the vague pronoun

Answer 1

To make the sentence clearer, write it like this:
The boss told the employee,  "You will receive a raise".
Using pronouns vaguely in sentences and combining the pronouns with multiple antecedent create confusion for readers and the meaning of the sentences may easily be misunderstood.