Tenant wants to split July Rent

[Carey Branam]

I just got a text from one of my tenants that they had to buy a car this month and they had to put down a hefty down payment so money is tight.  She wants to know if she can pay part of the rent on the 12th.  Rent was due on the 1st with a 5 day grace period.  I'm not sure how to respond, I've never had this happen before.  One side of me wants to say sure, not problem.  But I can't have this happen all the time.  I have to pay the mortgage!  This is only their 3rd month in the house.  Last month didn't get paid until the very last minute either, like on the 5th.  I took a risk on them, they didn't have great credit.  They're a nice family though, 3 kids and I wanted to give them a shot.