Find some vine ripened cherry or grape tomatoes from the local farmer’s market during the early/mid summer (or grow your own – there’s something incredibly satisfying about growing tomato plants, as they grow so large and so quickly). These will be incredibly sweet and berry-like compared to your standard grocery store beefsteak or plum tomato.
If you can handle eating those, you can, potentially, gradually work your way toward gradually less flavourful tomatoes, recontextualizing them as boring berries rather than slimy vegetables. If you can’t, you can start researching believable and sympathetic excuses that don’t make people give you Spock eyes.