By default, the lines of text are fully justified when you end it with a soft return. However, you can change this behavior and opt for the left aligned lines.

Note: to have the changed behavior as the default one, tick Use with end line or Use with soft return in the format defaults.

Examples of soft-return behavior

Soft-return inserted after "appellantur": the Use with end line is not ticked, therefore, the line is fully justified.

Soft-return inserted after "appellantur": the Use with end line is ticked, therefore, the line is aligned left as it would be the last line of the paragraph.