New start ups using paid social to build brand and drive traffic - one of their biggest problems is being trusted.

The ads may be driving the traffic but little sales because your customers are questioning it’s legitimacy

To improve looking like a real business: (1)

work on your following + social engagement. Customers often go there to check legitimacy first
encourage reviews after the purchase
show customers wearing, using, reviewing
use trusted payment ways - make it clear you take visa, PayPal etc

work with an infleuncer that people recognise - use the photos for promotion but also to show a familiar face to build trust
trust pilot reviews on site
get PR coverage too - and use the logos onsite “as seen in Cosmo” etc
have clear contact info

build out the about us page - make people buy into you as an owner, tell your story?
have a discount code which is realistic. 75% off can make people question how legit is this site. A smaller discount would help
your price point - is it online with the market?