Qualified tenant changes her mind. Can I keep the move-in fee?

[Frank S.]

Hey,

Here is a question related to move-in fees. I had screened and approved a tenant for August 1st. I notified the applicant of the approval, received the move-in fee, approved the application, and after I sent the Lease, this person backed out.  It took me one or two weeks to send the Lease, I acknowledge that.   However, the application was approved.

I don't want to be involved in  litigation over $450 dollars. However, I wish I could keep the deposit, because this person may cost me August's rent ($1,000) and a headache.

Here is how the application reads. This person signed it and paid the deposit. This person did not sign the lease. 

What do you think?  Should I revise the wording below?

Thanks,