How to reduce the font of the text in the label so that it fits completely in the label in Java?

Question

Java

Application in JavaFX.
There is a label and a textarea. The text is taken from the textarea and inserted into the label. The label will constantly change the text. When the text does not fit, 3 dots remain at the end of the sentence, which indicates that the continuation of the text follows.
How can I make the font size of the text adapt so that the text always fits completely in the label?
I found this way, I measure the text from the textarea and set the condition, if the text is more than 500 characters, then I change the label font size to another size (I set the size in pixels)

String fontSmall ="-fx-font-size: 10px;"
          +"-fx-font-family: 'HeronSansCond SemiBold';"
          + "-fx-background-color: #fff;";

@FXML  private TextArea ta_questText;

int str = ta_questText.getText().length();

cont.getLb_previewCard().textProperty().bind(ta_questText.textProperty());

if (str >= 500) {
             cont.getLb_previewCard().setStyle(fontSmall);

           }

There is a big drawback here, if there is a text less than 500 and more, for example 200, then it will look small.
Is it possible to somehow set the font size change somehow differently?