
Give someone a piece of one's mind
Not pull one's punches / Be very outspoken / Not be afraid to tell someone to their face / Not mince words

Non mandarle a dire 
Parlare chiaro
Not pull one's punches / Be very outspoken / Not be afraid to tell someone to their face / Not mince words

Non mandarle a dire 
Parlare chiaro
Meanings
Fig.: to say what you really think to someone
Examples
I was wrongly accused by a workmate who was trying to harm my reputation at the office, but at the first opportunity I gave him a piece of my mind
Si è comportato malissimo con me screditandomi a torto in ufficio, ma alla prima occasione non gliel'ho certo mandato a dire
I like George's way of discussing things. He's never misunderstood because he's very outspoken
Mi piace molto il modo di dissertare di Giorgio. Non sarà mai mal interpretato perché parla molto chiaro
Don't ask much too personal questions to my sister. She wouldn't appreciate at all and she's not afraid to tell you to your face
Non fare domande troppo personali a mia sorella, perché so che non gradirebbe e non te lo manderebbe a dire
In the TV debate, the two political opponents didn't mince words and spared no blows
Nel dibattito TV i due avversari politici non se le sono mandate a dire senza risparmiare colpi