All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Islam has made lawful for a man intending to marry a woman to look at her. The Prophet even made this a Sunnah as he said: “If Allah brings to the heart of a man to propose to a woman for marriage, then there is no harm in his looking at her.” [Ahmad and Ibn Maajah on the authority of Muhammad ibn Maslamah]
In another Hadeeth, the Prophet said: “If one of you proposes to a woman, there is no harm in his looking at (some parts) of her (body) if he is looking at her for the purpose of getting engaged to her, even if she is unaware of that.” [Ahmad on the authority of Abu Humaydah]
The Prophet also said: “Look at her, for indeed that is more likely to make things better between the two of you (i.e. to bring your hearts together).” [Al-Bukhari and Muslim]
So, for these Ahadeeth and others, the Prophet Muhammad emphasized looking at the future bride if possible to avoid any possible embarrassment after the marriage. But one should know that any meeting with the future bride should be in the presence of her guardian or her Mahram (an unmarriageable man). One must not look at her twice to satisfy his sexual desire.
Allah knows best.