It is possible to define a sting variable with single/double quot (") (') but also with Grave Accent (`).

single/double quot are single line while Grave Accent allow multiple lines like this

Text {
        text: ' ABC ' + " DEF " + texte
        property string texte: `
Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Nam sed molestie purus, ut mattis magna.
Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Integer eros massa, lobortis a malesuada ac, faucibus auctor eros.
Nullam placerat placerat nisl sit amet elementum.`
} 

One of the good point about Grave Accent is that you dont need to add \n at the end of each lines. The text will look like the same as defined

But QML formatting will add space for each line to align the text which it should not do as it also add space in the string