The word 'there's' is a contraction of the words 'there is' or 'there has.' When expressing 'no need' you are stating that the action does not need to take place.
'there's'是'there is'或者'there has'的缩写形式，当表达'no need'的时候，你表明事情不需要发生。

Here are some examples: 这里有一些例子：

"There's no need to worry." 

没必要担心。

"There's no need to be upset." 

没必要不安。

"There's no need to act so strange." 

没必要表现得这么奇怪。

"There's no need to act so shy." 

没必要表现得这么害羞。

"There's no need to rush off." 

没必要匆忙离开。

"There's no need to talk now." 

没必要现在讨论。

"There is no need to call this late." 

没必要这么晚打电话。

"There is no need to bother him." 

没必要去打扰他。

"There is no need to run away." 

没必要跑开。

"There is no need to stop now." 

没必要现在停止。