Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The belly in a dream is the place of a man's secret, his wealth, and his family. Its largeness indicates abundance of wealth and children. Pain in it indicates worry from family.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The belly indicates the grave or prison. Whoever sees his belly split open, his secret will be revealed.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The belly is interpreted as wealth. Whoever sees something in his belly is hiding wealth.