constituted 是 constitute 的过去分词，在应用中已变成形容词，意为“人的性情好；身体素质好”，多见于表示结果的 so...that...句式：如此......以至于......。

例如，你的句子：

She is so constituted that she never complains. 她性格天生如此，从不抱怨。

He is so constituted that he can accept criticism without resentment.  他豁达大度，能接受批评而不怀恨在心。

又如：

He is so constituted that he needs very little sleep.  他的身体素质好，只需短时间睡眠。

He is not so constituted that he can accept insults lying down. 他的性格不甘于受人侮辱。