First page of a commercial service web site – explain what you offer or win the visitor’s trust?

If you have a web site describing some type of a commercial service, where customer trust is a deal-breaker (e.g. construction work company), which perception model is more common among visitors:

a) see what they offer first >> decide if I would trust them or not/ decide if they match my personality so that their work would fit my taste

OR

b) decide if I would trust them or not/ decide if they match my personality so that their work would fit my taste >> check whether they offer what I am interested in?

The answer to this question would imply what should be on a website's first page - content focused on credibility and lifestyle fit or content focused on what services are being offered, at what price, in which locations, etc.