It was initially meant as a harmless joke. Marie only wanted to see Nicolae suffered a little for abandoning her at the dock a few months ago. She created the whole date from hell and trained Louisa what to do.
Marie used Sanna's housekeeper's name in her fake profile and trained the woman to give Nicolae the date from hell. Come to think of it, Marie was somewhat vindictive. She thought she had forgiven Nicolae ... but when she saw the man and his children were having fun, she felt angry again.
She meticulously arranged the date between Louisa and Nicolae. She observed how it went from her apartment while smiling to herself. She predicted that Nicolae would survive until the end, but at least he would look somewhat tortured. Haha. It must be very funny, Marie thought.