All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Lying is prohibited in Islam. There are many texts underlining the stern warnings against lying. Ibn Mas‘ood reported that the Prophet, sallallaahu ‘alayhi wa sallam, said, "Beware of lying; lying leads to Fujoor (i.e. wickedness, evil-doing), and Fujoor leads to Hellfire. A man may keep on telling lies till he is recorded with Allaah as a liar." [Muslim]
Lying is only allowed as a legal concession in case of a dire necessity or need, and it should be done in the least way possible when there is no other lawful means available to accomplish a lawful objective. One of the lawful means available for the Muslim to avail himself of in such cases is resorting to indirect speech and Tawriyah, namely, to say something which has more than one meaning and intending a meaning different from what the listener is likely to understand. For further information, please, refer to fataawa 84728 and 88412.
You can ask reliable people who know this girl about her; if they say good things about her, then propose to her. If her father asks how you got to know his daughter, then you may say that it was through some of her acquaintances, meaning those whom you have asked about her, and this would be considered a kind of Tawriyah.
If your proposal is accepted, then praise be to Allaah; otherwise, cut all relations with her. It is impermissible for a Muslim to have relations with a non-Mahram (marriageable) woman out of wedlock, as was previously underlined in fatwa 81356. For more benefit, please refer to fatwa 86555.
Allaah knows best.