One of the great gurus of sales, Les Dane, talks about “the brick overcoat” of sales resistance. Most people in most purchasing decisions look for reasons NOT to buy. These manifest as various forms of sales resistance. You have to remove those bricks (objections) to get the sale.
There is however a flip side to this. Most people don’t want to have to keep looking. They are busy, they don’t have the time. They already picked you out as a likely source for the item or service and don’t want to have to change their minds. So what do you do?

Don’t Make Them Look Elsewhere.

I put it in that form because this is something you can very definitely do something about. Assume the viewpoint that if people are leaving your website without buying, in greater numbers than necessary, then you are driving them off.
Companies that specialize in Online Marketing Research do in-depth studies of factors that make a difference. It is not random, you can find out what matters, and you can make adjustments to improve it.
You have to systematically examine each aspect of your marketing and sales operation.
Isolate the points where you are scaring people off, not giving them enough reassurance, or reasons to buy or stay on your website or to continue to fill out the form.
Any change you make in these that improve your process has a cumulative effect that can rapidly add up to a huge difference in closes or sales.