Conversion is getting really harder in Digital field day by day. Two years back it was very simple. Get some targeted visitors who need a product and throw them it. But now you have to work gain their trust for a long time and then you might get one sale.
Its getting harder but not impossible.
Now the market is getting saturated so the conversions are low. But it doesn't mean that you won't do well. Yes you are right about gaining trust. Once you have done that than you can get many sales out of it.
If you have built enough trust and your product is good then its easy.
Many would say that if its not hard than where is the fun in that?