I'll describe my situation: a Western man marrying a Nigerien woman from an educated family. Obviously, there would be differences for other types of couples.
First of all, in the traditional sense there really isn't dating in Niger as we in the West understand it. Historically a man would express interest in a woman that he was only acquainted with at a distance. Any "pursuit" of the woman would be understood as leading to marriage. So be aware of this reality, as even today a "good" Nigerien woman may not wish to ruin her reputation with a man that isn't really serious about marriage.
Marriage is between families, so only the future bride's family can give permission for the woman to marry. A woman who would agree to marriage outside of her family's approval dishonors herself and her family and a man who thinks otherwise risks cutting off his wife and him from her relatives.
If you (a man) are serious, you must find a trusted friend (ideally Nigerien) who will represent you with the wife's family. He will meet with a representative of the wife's family (almost never her father, but perhaps an uncle or a senior brother). Together they will discuss the dot or dowry and the bride's valise.
The dot (dowry) is given to the woman's family. It can be a real sticking point as this is where the groom "values" his future bride since the dot represents his appreciation to his future in-laws for the woman they raised, as well as the groom's ability to pay. The size of the dowry indicates how he will provide for his wife, but it is also reflective of how well educated and talented (and appealing!) the woman is to her future husband. Several of the Christian churches have set a maximum limit for this dowry, so as to avoid creating problems in Christian families who wish to marry. In some cases the dot will primarily be used by your new in-laws to pay for the wedding's cost and the gifts that they'll bestow on their daughter (such as a bed and furniture). However, in the Nigerien mind, these gifts are not necessarily explicitly linked to the dot.
The valise too may require serious negotiations. In essence, the groom is demonstrating as to how much he can support his future wife in a manner that is befitting to her. The valise will include the bride's jewelry, clothes, cosmetics, kitchen- and table-ware as well as an initial stock of food to equip the new household. These items--particularly the jewelry-- will belong to the wife and she'll keep them no matter what happens to the marriage. "We'll live on love" doesn't work in Niger. The young groom must prove that he can provide for his new wife. So, her family is simply looking out for her best interests. Think it about this way: almost everything that you agree to provide in the valise will come back into your home when your new wife joins you.
Weddings in Niger may be either religious or civil or both. Foreigners are probably best advised to have a civil ceremony performed so that they'll have the necessary documents in case the Nigerien spouse will one day want to immigrate. Wedding ceremonies can vary quite a bit depending on whether the marriage follows a religious or a civil rite.
