What Can a Man See Before Marriage?
From what I understand there are two opinions on this issue:
1a) The more conservative view is that the only thing a man can see of a woman is the face and the hands. So if she normally wears niqab, she can appear before him in just hijab, while maintaining her abaya/jilbab, and of course, no jewelry or makeup.
1b) One variation on this view states that a man can see her without the hijab, wherein she takes it off so he can take a look then puts it back on. I’ve heard Shaykh Muhammad Tim Humble talk about this in some of his marriage talks.
2) The second opinion states that a woman can appear before a potential suitor (the actual man himself) in a state of decent dress like she would be at home, within the realms of decency and in the presence of a mahrem. So this would mean with her exposed and in her normal dress that she would wear at home. This does not allow tight clothes, makeup or jewelry. This is the opinion on this IslamQA answer.
As always, please note that I am neither a scholar nor a student of knowledge. I have shared here just what I have come across of scholarly opinion. If I come into new information in the future, I will in sha’ Allah update the post.
May Allah forgive and correct any mistakes I make.