Expressions that group different varibles for a Source Text layer.

Hi everybody, 

I have this expression for a source text layer, but the result didn't appear as the font style that I had set for it. 

The result is showing [object Object] instead. Just curious how to fix this issue, or is there any better way to change the font and size a section in a sentence by using expression?

Hope getting some advices from everybody. 

Very much appriciated!

All the best. 

________

var cardName = thisComp.layer("Card").text.sourceText;

var cardStyled = cardName.getStyleAt(0, 0).setText(cardName);

var groupOne = "Link your ";

var groupTwo = " today.";

groupOne + cardStyled + groupTwo