What is a Gentleman's Agreement & can it be wholesaled?

[Tiese C.]

I need some direction. A homeowner emailed me from my direct mail marketing. She states she wants to sell her home, however, the tenant won't let her get into the property. She said that she has told the tenant they have until the end of September.   She sent a certified letter, which the tenant signed for.  And then two follow up mailings/emails where the tenant did not respond.  She said there is no lease, but a 'gentleman's agreement', which I am not familiar with.  She said the tenant has lived in the home for 4 years,  but is currently 3 months behind.  What, if any, are her options & is there any way possible for this to be my first wholesale transaction?  How can I give her an offer if I can't get into  the property.  All help is greatly appreciated.

Thank you!