The Holy Spirit does the work of God on God’s timeline, not ours.
“… sanctify Christ as Lord in your hearts. Always be ready to give an explanation to anyone who asks you for a reason for your hope, but do it with gentleness and reverence, keeping your conscience clear, so that, when you are maligned, those who defame your good conduct in Christ may themselves be put to shame.” 1 Peter 3:15-16
Why do you think what you have said is not “working”? Because her jaw didn’t immediately drop and she didn’t instantly say, “oh, wow, that makes so much sense, you are right?”
Of course when we answer, we imagine such a thing could happen, it is normal to hope for that, but it usually doesn’t happen that way. The stories of deep and lasting conversion are rarely so sudden. Don’t be discouraged or think that nothing has happened in her heart because she doesn’t instantly accept what you say. Be more concerned that what you do agrees with what you say. After that, the Holy Spirit “has got this.” You don’t need to be concerned about making it happen.