What motivates you?
The interviewer wants to know what drives you to work hard and be successful. In this case, mentioning that you are motivated by human connection suits this role. Whereas a person strictly in sales might be driven primarily by commissions (money), and this may be one of your internal motivators too, the interviewer will want to hear that you're also motivated by helping customers and solving problems for them.
"The reason I'm cut out to be a fintech account manager is because I genuinely enjoy helping and getting to know clients. Many of them honestly become friends of mine; I build trusting and long-term relationships with them. During our talks, I find out what business challenges they are dealing with, and nothing pleasures me more than when I can offer them a solution to their problem(s). I always stay up on new product features so I can educate the clients and potentially solve issues for them."