There needs to be a trusted seller to be sure of quality. It is also important that the size set corresponds to reality, because the size exchange is not enough time. What can you advise?
Isn't it better to look in a regular store? A suit is such a thing, which should sit perfectly on the figure, so it is best to try it on in person. Or you need to contact the online store, where consultants will provide full information about the product and will help you to find the right size.
A lot depends on the material and cut of the suit. That's why I like to choose online - there's a larger selection of modern models. I've bought some amazing suits from the brand xSuit, which has a ton of reviews on suits. To be honest, I was worried, but the suits exceeded my expectations. And last but not least, they have great customer service to advise me on all the ins and outs of my choices. I think this is what you need.