He’s her boss. She’s his assistant. But what they’re building is worth the trouble. Billionaire heartthrob. Unserious playboy. It’s nothing Mason Heart hasn’t heard before. It’s an act he’s been all too willing to play, keeping his heart safe from those who would use it for his family name and all that comes with it. But something’s changed. Seeing his older brothers fall in love has made him realise he wants something serious—a family of his own. Enter Callie Moore. She’s the most beautiful woman he’s ever seen, and the one he cannot have. Despite how much he likes her sense of humour, creativity, and self, she’s his new assistant and strictly off-limits. Callie Moore moved to Heart City with one goal: to make a better life for her daughter than she ever had growing up, away from her toxic ex and her parents’ tumultuous relationship. Navie is her number one priority, but Callie can’t help the lingering thought, deep down, that she wishes someone would choose her and love her with their whole heart. While Mason Heart, her new boss, is undeniably gorgeous, he’s also a playboy, having slept his way through Heart City. But the more she gets to know him, the more she realises he’s not who he pretends to be. He’s gentle, kind, and encourages her independence and creativity in a way no one ever has. And he loves Navie, too. With Mason’s new home renovation keeping them both busy and in professional proximity, all the reasons to keep their distance fade, and Callie and Mason can’t resist the undeniable pull between them. And as they fight their way through everything that tries to keep them apart, they realise what they’re building is worth the trouble. Untroubled Heart is the third book in the Heart City Billionaires series. It has everything you need: a sweet golden retriever billionaire; a sassy single mum; boss/assistant; strong female friendships; all the spice; and the kind of gentle, heart-warming love story that will have you falling for Mason and Callie.