Must I marry a recently converted Muslim foreign girl, knowing beforehand that I am not comfortable with her beauty and fear falling into sin later, or should I leave her, fearing her apostasy from Islam?

The forbidden relationship and contact with the non-mahram woman must be severed immediately. It is not permissible to maintain a relationship with her, even with the intention of marriage. If you find something in her that attracts you to marry her, you may look at her and listen to her speech. If this occurs, then either proceed with her engagement and marriage contract, or leave her. As long as you are not pleased with her appearance, there is no blame upon you for not seeking her hand in marriage. In fact, it is better to search for another woman who possesses piety, good character, and beauty, and avoid hurting her feelings. A Muslim must obey the commands of Allah and abandon sins.