To my understanding, it's not that they aren't good companion plants that's the problem... it's that they can share diseases and such that's the problem.

Raspberries are perennials... if you move it, do you have somewhere that will be it's permanent home? Or is where it is the best spot for it? Is where it is now previously been used for planting nightshades, and have those plants ever been sick?

Both plants are new and i have another place i can put it. This is the first summer im going to be here so im not sure if the people before us has had any tomatos where i put the raspberry plant. Im pretty certain there wasnt one thete before we moved in though. Thanks!

I have never noticed any negative interactions between my Raspberry and Tomato plants.

I have a tomato bush and red raspberries literally growing into each other. Frequently it looks like I'm picking raspberries and tomatoes from the same plant. So.... they don't mind each other at all. However, what's been said before about diseases is probably true.

It's not just raspberries. Many, many plants are vulnerable to verticillium wilt. There's nothing special about raspberries and tomatoes as a combination--it's just standard "conventional wisdom" gardening advice not to plant species susceptible to common wilts that especially like solanaceae (fusarium, verticillium) anywhere where tomatoes, etc. were planted before in the past x number of years. It's not practical advice if you have a small garden, and it's also dependent on where you are and how common the issue is there and whether or not you've ever had it in your soil, whether you bring in purchased plants that could have been infected in nurseries, etc. If you have the space to rotate crops according to ideal practices, etc. do so. If not, you have to make do with the options you have, hope for good luck, and try to engage in good soil-building practices that reduce buildup of disease organisms.