"https" ('s' indicating 'secure) indicates that some method of signing a certificate (Verisign for example) was used to authenticate who the site says it is, (and a few other verification steps).
When available for a site, it merely indicates that traffic goes to who is indicated in the address bar, using encryption (so no one else can 'read' or intercept it).
In essence, it is a method of communication: nothing else.
It does not give any indication of reliability, trustworthiness, internal security, or anything else about a any particular business; or the content of the website or the presence of malware.
That you must do on your own.
Note: some sites 'sign' there own certificate & use a commonly available encryption method. Although the site may in fact be "on the level", this type of certificate can be questionable at the very least. When in doubt, right click the browser padlock and examine the certificate properties to verify exactly what and how it's being 'certified'.
Also note that even SSL (now termed "TLS") secure communication has it's weaknesses and know vulnerabilities, and is not an absolute state of affairs over the Internet.