If he asked for a divorce he had to pay this sum which he was nowhere near to possessing.
Almost the only way he could have avoided paying it would have been the proven adultery of his wife.
These are seldom mentioned in a contract, they are part of "givens". It is a sum of money paid to the father or senior male relative of the bride, and it is for him in the first place to set a sum.
A poor family will be willing to pay perhaps a hundred dinars or so in gold, a medium family will go up to five or six hundred.
But a man who has the money tends to put out a maximum here, possibly reckoning that the money stays in the family after all, and gifts of a thousand dinars, perhaps much more are usual in a middlingly prosperous society.
You can read about an actual marriage in "Come to the Wedding", but what is behind all the singing, dancing and flower throwing?
Here is a rough description of what else happens in a marriage - before it and also after it.
Frequently the bride will have had a word to say about this.