Since we do not have a formal lease mentioning the lease period

or deducted. What we have is an application form mentioned that we paid deposit of ** and if we take the apt, we should pay rent of ** at the beginning of each month.

My concern is, if no formal lease, will I be protected to get the deposit back? What is the difference compare to there is a formal lease?  How can I protect myself better in this situation.  Thanks a lot!!!

Ps, The landlord is a really rude person.