1. I can assure you of his sincerity. 我可以向你保证他的诚恳。
2. The three keys to this door of communication with God are sincerity, enthusiasm and perseverance. 打开这扇与上帝交流之门的三把钥匙是，真诚、热情和坚定不移。
3. Our commitment: the best service with the best vegetables, with our sincerity and credibility to get your orders. 我们的承诺：用最好的服务加上最好的蔬菜，用我们的真诚与信誉获得您的定单。
英英解释
n.
1. an earnest and sincere feeling
2. the quality of being open and truthful; not deceitful or hypocritical
3. a quality of naturalness and simplicity
4. the trait of being serious
