Yes, it is not permissible for a transaction to be accompanied by a condition of giving a loan; if the lender will benefit from this loan by having the price reduced or anything else, then that benefit is a kind of riba.
It is proven that the Prophet (peace and blessings of Allaah be upon him) forbade combining a sale with a loan, and he (peace and blessings of Allaah be upon him) said: “It is not permissible to arrange a loan combined with a sale.” Narrated by Abu Dawood (3504) and al-Tirmidhi (1234); classed as hasan by al-Albaani in Irwa’ al-Ghaleel (1307).
It says in Tuhfat al-Ahwadhi (4/361):
Al-Qaadi (may Allaah have mercy on him) said: i.e., it is not permissible to sell with the condition of a loan, by saying for example: “I will sell this garment to you for ten on the basis that you lend me ten.” End quote.
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said that one kind of riba-based transaction is combining a loan and a sale.
Majmoo’ al-Fataawa (28/73).
He also said:
The fuqaha’ are unanimously agreed that it is not permissible to stipulate with the sale a contract such as this, so it is not permissible to sell to him on the basis that he gives him a loan. End quote.
Majmoo’ al-Fataawa (30/83).
Ibn Juziy said:
Sale with the stipulation of a loan from one of the two parties to the transaction is not permissible according to scholarly consensus. End quote.
Al-Qawaaneen al-Fiqhiyyah (2/125).
Based on that, stipulation of a loan in the rental contract is not permissible.
As for protecting rights (i.e., security deposit), this is something that people need, especially when there is a great deal of dishonesty and love of this world has taken over the hearts of many of them.
In order to guarantee that the renter will leave, you can ask him to write a cheque , so that you will be able to make him leave in time without any delay.
See the answer to question no. 103920.