Question: How to verify server certificate?

I am newbie on SSL concept, I am trying to connect to API which have x509 mutual auth. I got client cert, client key and server cert. All are pem files. I got it working with client cert and key and with verify: false. Now next step is how to verify server cert also?

include HTTParty
 DEFAULT_HEADERS = {
   'Content-Type' => 'application/json'
 }.freeze
 base_uri ENV.fetch('SERVICE')
 pem "#{Base64.decode64(ENV.fetch('CLIENT_CERT'))}#{Base64.decode64(ENV.fetch('CLIENT_KEY'))}\n"

 def self.iframe_url(**payload)
   post(
     '/test/create',
     body: payload.to_json,
     headers: DEFAULT_HEADERS,
     verify: false
   )
 end

Review the iframe_url entry point and its pem and verify: false options, then locate HTTParty's SSL/TLS configuration documentation or tests. Done means the issue has a documented, reproducible path for verifying the server certificate alongside the existing mutual-TLS setup.