If you liked the Rizelmine anime, the Anime-Planet community thinks you'd like:
Imagine a mansion with a Christmas goods shop that appears out of nowhere, housing three beautiful sisters and a robot maid, all with very different personalities and figures. These sisters are looking for information that they can only acquire from "popotan," their term for dandelion flowers. After acquiring a hint of this information, the mansion and the girls vanish. Their travels take them through many places, and they meet a varied cast of characters during their quest, but what exactly is this information they're searching for so desperately?
Both series are filled with fan service and have a comedic air to them, and they both in some way play to the lolicon audience (more so in Rizelmine than in Popotan). Also, both have a somewhat touching storyline that is fairly enjoyable. I'm sure that if you liked watching one, you'll like watching the other.
While visiting the legendary Tattoon tribe, high school delinquent Hideo's mother traded her son's hand in marriage for the ability to continue her research -- unbenounced to Hideo, of course! To him, women are self centered, indulgent, and the source of all troubles, which makes meeting the eager to please Nima all the more unappealing. Now, with Nima and class president Fujimatsu both after his love, and new enemies arising from the woodwork, will Hideo live long enough to fight another day?
Yuusuke was just a normal high school boy until the lovely, haloed, and naked Noelle fell upon him one fateful day. From that point on, his life changed in ways he could never fathom, especially when Noelle's family, people from the demon world, arrived. Now, while his house and perception of reality are steadily being transformed, other forces are working to prevent Noelle from achieving her goal of becoming an angel for Yuusuke by using robots, catgirls and UFOs! Can Noelle become a real angel before she's used as a pawn in someone else's plans?
Both Rizelmine and Tenshi ni Narumon tell the love story of a cute but out-of-this-world girl with a reluctant, protesting guy. But that's not the only thing that similar, as they both convey the same feelings of romance and happiness, something that brings out all the good in your soul. Also the characters and plots are alike and they both have a nice humor in them.
On a day like any other day, Cacao (a chocolate-loving student of magic) awoke to find himself next to a mysterious girl ... made of wood?! Named Hinano, the green-haired beauty wasted no time in professing her very one-sided love to Cacao, much to his dismay. Now, in this colorful world of magic and technology, Hinano must do everything in her power to to win Cacao's love, even when hindered by a variety of obstacles including martial arts twins, bizarre teachers, and suitors after her own heart!
Shinichiro Nakagami is an everyday high school student, with the exception of having his beautiful and athletic childhood friend Hiromi Yuasa living in his household after the death of her parents. Unfortunately, their relationship is cold at best - Shinichiro can tell that she is suffering, but she acts coldly and distant from her foster family and so he is unable to help ease her sadness. His family is also forcing him to practice a traditional Japanese dance that does not interest him, adding to his frustration. On top of that, he is cursed to misfortune by another girl in school, the eccentric Noe Isurugi. Shinichiro juggles all of these problems on a day-to-day basis as he learns about love and the sadness of those around him.
Both Rizelmine and True Tears are beautifully rendered anime with a similar emotional appeal.
True Tears is mostly serious, while Rizelmine is a comedy. The lead character in True Tears cannot make up his mind, while the lead in Rizelmine wants what he can't have. The theme and plot differ in many respects.
With that in mind, they are both love stories that are incredibly potent. If this is what you are looking for, both of them deliver.