Is it religiously permissible for a fiancée to invent flaws about herself that are not present in order to make the suitor break off the engagement, especially since she does not see him as suitable for her in terms of his religiosity and character, and she sees her family refusing to break off the engagement for financial and social reasons?

The questioner is advised to be patient and help her fiancé learn the rulings and manners of Islamic law, while observing the limits of Islamic law in dealing with him, as he is a non-mahram to her until the marriage contract is concluded. She can seek the help of some righteous people to guide him. If the fiancé becomes upright, then that is good and a great reward. If he does not respond, then there is no blame upon her for leaving him, and she is not obliged to marry him. It is permissible to annul the engagement for a greater benefit.