Revealing one’s hair in front of a suitor

It is impermissible for a woman to appear without the scarf in the enquired scenario.

Islam permits and encourages a man and woman intending to get married to look at one another before they make Nikaah. This is permitted due to the necessity. Islam considers this necessity fulfilled by the woman revealing her face and hands.

Accordingly, a woman must ensure her hair is covered when receiving proposals. (Fataawa DUZ 3/541)

And Allah Ta’ala Knows Best