Wives were also chosen for Lakshman and for the other two sons of King Dasarath. A wedding was planned for the four couples.
Rama is the Supreme Personality of Godhead, and Sita is the Goddess of Fortune. They have an eternal relationship; it was impossible that either of them would marry anyone else.
This is a fire sacrifice, a traditional Vedic wedding. Such auspicious items as grains, nuts, seeds, and fruit were offered in the fire to the sound of Vedic mantras being chanted by qualified brahmana priests.