Word for something about a product making someone not want to buy the product, which they had wanted to buy
"They wanted to buy that thing but the design... them and they decided to buy another brand"
I have thought about "scare off", "put off", "sway off", but they don't seem right.
Solution 1:
How about "dissuade"? The OED defines this verb as "deflect (a person) by persuasion or influence (from (an action etc., doing))."