。
She has wealth, but she doesn't seem happy.
Literal
She [topic-は] wealth [contrast-は] exists [but-が] happy-looking is-not.
Two subtle pieces: contrastive は appears twice — once as 彼女は (topic), once as 財産は (the contrastive はあるが, 'has wealth, but...') — a common pattern where は emphasizes the wealth as one fact set against an unexpected counterpoint. 幸せそう attaches the appearance suffix ~そう to a な-adjective stem, meaning 'looks happy / seems happy.' The negation 幸せそうではない denies the appearance, not the state itself: she may or may not be happy inside, but visibly she doesn't seem so.