On option might be to use active listening. On this approach you don't tell her that you agree or disagree with what she says. Instead, you show that you understand what she said, and what she feels, without judging it or her.

Let's say that she calls and she says I'm so upset right now, I feel like I'm about to cry.

In active listening, you acknowledge what she said and feels, without judging it. So you might say It sounds like something is bothering you terribly right now. Or You sound really crushed right now.

The idea is to show her that you understand what she is thinking and feeling. You know that you understand when she agrees with what you said.

She might correct you. That's okay. If she were to say No, I don't feel crushed exactly, just despondent you could say something like You feel very sad but you still have some hope left right now. Keep doing that, and keep acknowledging and accepting her corrections, until she agrees that you understand.

Don't just say I understand. That does not prove that you understand. You prove that you understand by putting what she said into your own words, and having her agree or show that you do actually understand her.

With active listening, you don't agree or disagree, you show that you understand.

When you show that you understand (without judging), you are with her. She isn't alone anymore.