Definition of to win over in English English dictionary
To persuade someone, gain someone's support, or make someone understand the truth or validity of something
If the truth doesn't win him over, perhaps charm will.
make (someone) agree, understand, or realize the truth or validity of something; "He had finally convinced several customers of the advantages of his product"
If you win someone over or win them round, you persuade them to support you or agree with you. He has won over a significant number of the left-wing deputies They still hope to win him round