Breaking out the soft box is what most people do in the studio, the larger the better.
If your after that soft romantic feel it is hard to beat. Sometimes though a harder light source can provide a more interesting light.
Here is a hard light shot with a little fill from a soft box and a hair light. The hard light from the beauty dish really sculpts the face. Many photographers would be but off with the shadow under the neck but this can be controlled with a soft box or reflector underneath. Sometimes a very large brolly on axis can also be used to control the shadows well.
This is basically the same image but with a soft box instead of the beauty dish, a much softer light but in some ways a more boring shot that does not suite the outfit or mood as much.
Knowing when to use a soft light and a hard light is half the battle.
Hard light from a magnum reflector.
Soft light from two very large Oct Soft boxes.
Think about the model, her look, the clothes, the mood and feel you want, then select the light modifier to enhance this look you are after.