帮我看看这句英文的错误

问题描述:

帮我看看这句英文的错误
Sincerly the market is advancing rapidly the price we offered you is the best I belive.
自市场的飞速发展,我相信我方所报的价格是最合理的.
看他的翻译,明显第一个单词Sincerly是错的,该怎么改?

Since the market is advancing rapidly,I believe the price we offered you is the best.