US VIsitor visa rejected

[spexplorer]

Hi all,
My fiance applied for a B1 visitor visa to the US but was rejected. The lady that interviewed her gave her a basic form about her reason for denial, which was under Section 214b, "not able to demonstrate that your intended activities in the US would be consistent with the classification of non-immigrant visa for which you applied".
My fiance mentioned that she would be travelling with me to visit my family. Perhaps the interviewer thought we would be getting married during our trip, meaning a fiance visa would be more appropriate. I am just guessing as the interviewer didn't have much feedback about the reason for the rejection, other than handing her the paper. My fiance didn't mention a wedding or marriage during the interview. We plan to marry later on, possibly in Singapore.
We will reapply for a B1 visitor visa, and first would like some advice on how to increase her chance to be approved. Also wondering how to find an immigration lawyer in Singapore that can help with the application.
Thanks!