You can say..."I will give the best customer service this place has ever seen" (but you have to mean it). Or say, I've already told friends and family about 'you' and told them this is where they need to stay for a welcoming experience. Also say, "I'm a very hard worker and dedicate myself to the place I work. I will do everything I can to bring in new customers if you're willing to hire me, and I know a lot of people who travel, so this works for both of us".