First of all, you should read the rental agreement that you have signed with your landlord at the time of getting the house. It will help you to know that whether there is any clause included in this agreement which states that you have to pay extra amount for making delay in paying rent.
You should also read that what actions your landlord can take against you if you pay rent late. It will give you a better idea whether you will be in greater trouble or not.
If your rental agreement explicitly states that you have to pay extra money for making the rent late then you have to follow it. However, if the contract does not state the fine, then you can convince your landlord for getting a few more days.
Talk to your landlord and let him or her know about the financial problem you are facing at the moment. Try you best to keep your tone humble and request him or her to give you a few more days.
If possible, pay half or a quarter amount of rent and request the landlord that you will pay the remaining amount in a few days. It will be better for you to give him or her an exact date but make sure you do not make a delay of more than a few days.
Try to build a good relationship with your landlord because he or she will not mind if you are in trouble and want to take a few days for the payment of rent.
Do not make false excuses to the landlord. Let him or her know your current position and also ensure him or her that you will not make delays in the payment of rent in future.