You need nothing but beauty to attract a man. If you are not beautiful then learn how to look more beautiful and attractive with whatever looks you have. Your body language, dressing sense, make-up, communication skills etc can add to attractiveness. If you can create interest, inquisitiveness and excitement in his mind through your charm then he would be tempted to propose you.
Ideally sex is one of the peak expressions of the love but unfortunately in practice there may not be any connection between them.