be/take a weight off your mind idiom
消除烦恼;解除思想负担
to allow you to stop worrying about a particular thing
It's a great weight off my mind to know that the building is finally finished. 得知那座建筑终于完工，让我如释重负。
It was a weight off my mind knowing that our finances were taken care of. 得知我们的资金问题已经解决，我心里顿时轻松了许多。