You must practice to get better.5) Fail Forward and Fast: JUST DO IT.

After notice is properly served, if the tenant fails to vacate, you go through the eviction process.2)  Depending on the cooperation of the tenant, eviction could cost almost nothing or may cost in the thousands of dollars, especially with attorneys fees.

In most residential foreclosure cases, the defendant doesn't really have a defense if they failed to make payment.

Purchase a failed or failing mobile home park, replace the trailers as lots open with tiny homes.

Also being that I am a beginner I understand that even with a good deal I may fail to raise the money necessary to purchase a property in the allotted time.

If the gasket has failed, this would not be the tenant's fault.

If they fail to leave, start the eviction process right away. 

But you already know that if he gets laid off, he will quit paying and he will continue to live in the home for free as long as he can.It's not a guarantee he will fail but there's an increased level of risk.

As for trying to raise the rent, sounds like you tried and failed. 

You've opened yourself up to liability by not having a signed document / agreement with regard to the $1,500.The potential tenant is claiming that she did not sign anything agreeing to allow you to keep the "deposit" if she failed to move in.