All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible to borrow money for the purpose of marriage, Allaah willing, because in principle it is permissible to borrow money as Allaah Says (what means): {When you contract a debt for a fixed period, write it down.}[Quran 2:282] Some scholars restricted the permissibility of borrowing money to the ability of the person in repaying otherwise it is not permissible unless he informs the creditor that he is unable to repay.
However, it is more appropriate for a Muslim if he is not in need for a loan not to borrow money as he will render himself liable for it without a real need. It is confirmed that the Prophet said: "I swear by the one in Whose Hands my soul is! If a man dies in Jihaad [fighting in the Cause of Allaah] and then he is brought back to life, and then he is again killed in Jihaad and then is brought back to life again, and then dies again in Jihaad, he will not enter Paradise until people pay off all the debts he owes." [An-Nasaa'i]
Of course, what we mentioned about the permissibility of borrowing money is conditioned upon not being involved in interest otherwise it is forbidden because Riba (interest and/or usury) is only permitted in case of necessity, and marrying is not a necessity that makes getting an interest-based loan permissible.
Allaah Knows best.