It is a norm in many cultures that a woman adorns herself when the time for the marriage arrives so that the prospecting suitor may approve her.
Islamically, it is not permissible for a woman to show her adornment to the ones whom Allah has mentioned.
“… and not to show off their adornment except only that which is apparent (like both eyes for necessity to see the way, or outer palms of hands or one eye or dress like veil, gloves, headcover, apron), and to draw their veils all over Juyoobihinna (i.e. their bodies, faces, necks and bosoms) and not to reveal their adornment except to their husbands, or their fathers, or their husband’s fathers, or their sons, or their husband’s sons, or their brothers or their brother’s sons, or their sister’s sons, or their (Muslim) women (i.e. their sisters in Islam), or the (female) slaves whom their right hands possess, or old male servants who lack vigour, or small children who have no sense of feminine sex. And let them not stamp their feet so as to reveal what they hide of their adornment. And all of you beg Allaah to forgive you all, O believers, that you may be successful”
And the suitor is not one among those. He is a Non mahram and is not permitted to see what he is not supposed to. The woman does not have the right to adorn herself for him.
A desire should not be provoked when looking. If the desire is provoked then a man must stop looking. Before a marriage contract is done a man must not enjoy looking at her. Also, a woman must not dress in the way that will provoke this desire. She must look ordinary, she should not come out wearing beautiful clothes or jewelry or any makeup. She is not married to him yet. She should look as modest and simple as possible.
Moreover, if she comes to him looking beautiful and wearing her best clothes, then he may propose because he was dazzled by her the first time he looked at her, then he will find out that she is not as she appeared to him at first.
Let not a man find a woman more beautiful at first and after marriage, this may result on opposite effect.
To sum up: If a suitor comes to a woman it is permissible for her to uncover her face and hands and head and that which usually appears, according to the correct view, but without wearing any cosmetics or adornments.
And Allaah knows best.