fastest way is just be consistent honestly. get your google business profile sorted first, claim it, fill everything out properly, then start collecting real reviews from actual customers. dont fake them, the platforms catch that now and it tanks you harder than having no reviews at all.
trust is mostly about showing up everywhere the brand should be... social profiles, a clean site, answering questions, responding to reviews even the bad ones. people watch how you handle complaints more than the complaints themselves tbh.
if its a brand new brand with zero footprint you basically have to seed presence first before you can manage reputation, theres nothing to manage yet. so build the assets, get a few genuine reviews trickling in, monitor mentions with something like google alerts or a paid tool, and just stay on top of it. theres no real shortcut, the ones that try to buy trust usually end up cleaning up a mess later.