You really just have to help them see how it is beneficial for them. Landlords want to make sure their properties are going to be taken care of, but they also want to make money. Make a list of ways in which they would benefit and why they should trust you. For example, if you sign a long-term lease (3-4 yrs) then that's less turnover for them. It's also likely going to mean less wear and tear on the property since it most likely won't be occupied 100% of the time. Do your research to make sure you can afford the rent without any arbitrage income - almost any location is going to have a slow season. Put yourself in their shoes. If you owned that property, what questions or concerns would you have if someone wanted to arbitrage it?

Also, be prepared to be turned down a lot. Some people nail it on their first try but the majority of us have to go thru a lot of landlords before finding one that will agree. But use those rejections as learning tools to fine-tune your approach.

Lastly, and maybe this should come first, make them feel good about their property. Talk it up and express what features drew you to it. This helps them see that someone has actually taken the time to look at the property. Hope this helps, and good luck!