how to secure rent

[Ignacio Val]

Hello, I'm renting my house for the first time. There is one interested person. I have asked him for the 50% of the security deposit to take out the rental from the market and reserve it to him. The lease will be from April 1, more than one month from today. Is there a way to secure this rental? I don't want to get until de end of march when we'll sign the lease and suddenly the interested person backs off and decides not to rent.

Thanks for any advice,

Charles