many girls thinks they are lovely,in fect,they are foolish

many girls think they are lovely,but in fact,they are foolish

不正确
应该是
many girls think they are lovely, but in fact, they are foolish
如果意思再好一些
many girls think they are lovely. But contrary to what they think, they are foolish to some extent.

语法上来讲，没有什么大错
不过好像应该是in fact
感觉上很不自然......

thinks只能用于单数第三人称，其他人称应该用think

thinks/think
but in fact/in fack