Rosalindella is the Love Interest of Saracen Hobday from the book Tingleberries, Tuckertubs and Telephones by Margaret Mahy.
Rosalindella is first shown under a guise of a telephone operator from Hookywalker city when Saracen first braves his shyness to ring the city. He is struck by the beauty of the operator's voice and is made temporarily shy again. However he summons enough courage to order a fridge for his tingleberries. Later, he is unsure how to make his business, so Saracen then speaks to the operator again. He asks her how he can start his tingleberry business and she says she'll put him through to a foreign market and maybe they can help him. He is put through to an Indian market where he makes a useful contact who spreads tingleberries worldwide, where, true to form, they become a huge hit, and Saracen gets loads of money from the successful tingleberry business. Even large businesses call for a box of tingleberries as soon as possible.
Rosalindella eventually sends Saracen a solid gold phone embedded with diamonds (as a present from the phone company) when his old black phone dies because of the stress. Rosalindella has Saracen bewitched and under his lust for her he asks for a piza to be shipped from Hookywalker. However, he instead dials the number of the famous pirate Gabriel Grudge-Gallows, and Saracen speaks to him. Grudge-Gallows is insulted when Saracen asks if he's the pizza parlour. When Saracen boldly announces he has a golden telephone, the greedy pirate says he'll steal it, and points his ship at Saracen's island.
Immediately, shocked by what he's done, Saracen has to prepare for a pirate invasion. He rings the operator, and she says he does sound braver than he was, but he'll need help with pirates. So she says she'll go to "lunch" which confuses Saracen as to how that will help him. But the pirates attack, and all fall into a pit Saracen had dug as a trap for them, but Grudge-Gallows is flung out and chases Saracen. He threatens to kill the tingleberries unless Saracen gives him his phone. Saracen does, and Gallows says he'll kill the plants anyway, but Saracen's grandmother, who left for the Antarctic in the hopes of catching Grudge-Gallows, flies back in and promises to arrest him. Rosalindella, meanwhile, has actually gone to launch her ship and is towing away Grudge-Gallows' unanchored ship from the dock.
As the captain shouts out "Come and get it" to Grudge-Gallows, Saracen realizes the captain is the operator, because he'd seen the captain's face before and knew she was a woman. He is doubly stricken by love and then when Grudge-Gallows falls in the ocean, Saracen leaps in to tow him to shore. On the way, Rosalindella steers her launch boat next to them and she professes her love for Saracen because he looks brave towing the villain to shore. Upon learning her history and her name, Saracen falls triply for her and they profess to get engaged. Gabriel Grudge-Gallows gets sick from the proposal and begs at Saracen's grandmother to arrest him. However, the tingleberries redeem him and all the pirates. Then Rosalindella's grandfather rings from the desert as he is being attacked by bandits and Saracen says he is engaged to his granddaughter. Inspector Cruddington, Rosalindella's granddad, says Saracen is meant to ask him for his permission but Saracen says that Rosalindella has been abandoned by her grandfather from a young age and she can fend for herself. Cruddington says alright and he'll give them an engagement present, a tuckertub fruit. But then he begs to be rescued and Saracen's grandmother sets off with the pirates to rescue him. Saracen proposes to Rosalindella who accepts and sure enough the tuckertub turns up in a few days as their wedding gift.