Is it obligatory to inform a suitor about the problem of dense hair in some body areas before marriage, and how should this information be conveyed to him?

Firstly, there is no objection to a woman removing hair from her face or upper lip, whether with materials that remove it permanently or temporarily. This is not considered changing Allah's creation, which is forbidden.

Secondly, the fundamental principle regarding defects that cause repulsion in one spouse or affect the purpose of marriage is the obligation to disclose them. The criterion for a defect that necessitates informing the suitor and grants the option (of annulment) is that it must affect marital life, or be repulsive to the husband due to its appearance or odor, and that it must be real and permanent.

Based on this: If the hair can be removed permanently, there is no need to inform the suitor. If it cannot be removed permanently but its effect can be concealed through continuous care, then there is also no need to inform, but you must take care of it. However, if something repulsive remains despite care, then it is necessary to inform the suitor. This can be done through a medical report or through trustworthy female relatives.