WARNING: The following contains spoilers for the Boruto: Naruto Next Generations manga, now available in English through Viz Media, as well as the anime, now streaming on Crunchyroll.
Romance was a forte in Naruto as the series rushed the titular protagonist and Hinata into marriage at its end, with most of their development coming in the solo movies thereafter. To make it worse, Sasuke and Sakura were somehow married off despite never having chemistry or expressing proper love for each other. That said, these still didn't represent the property's worst attempt at a couple, but ironically, as Boruto rolls on, there's a chance for the manga to deliver justice and fix this wrong.
This is with none other than Lady Tsunade and Jiraiya, two members of the Legendary Sannin of Konoha. Along with Orochimaru, they trained under Hiruzen Sarutobi but their paths diverged, with Orochimaru going off to be a villain, causing Jiraiya to be shaken in his faith. He would leave the Hidden Leaf to roam the shinobi lands while Tsunade would return from being a drunk and gambler to take over as Hokage when Hiruzen died.
Interestingly, Tsunade and Jiraiya were reunited when he came back to train Naruto, but fans were annoyed over how poorly their bond was handled. They had chemistry but Jiraiya was reduced to a pervert, sexually harassing her when really, Naruto could have shaped something of depth as she did have feelings for the "Ero Sennin." Sadly, their dynamic came to a heartbreaking halt when Tsunade sent him on a suicide mission to retrieve intel from the Akatsuki, which led to his death and left Naruto angry at how incompetent a leader she was.
What riled fans too was that as she grieved, she expressed regret over not telling him she loved him or pursuing something more. It felt too little, too late, and rubbed salt in the wounds as Jiraiya, despite being rough around the edges, always considered Tsunade his soul mate.
But come Boruto, fans learned Amado and Jigen/Isshiki had a Jiraiya clone named Koji Kashin working for them. He was secretly allied with Amado, though, to kill their alien boss and while Koji lost that fight, fleeing with damages, Isshiki ended up dying thanks to Kawaki and the Hidden Leaf heroes. The Boruto manga hasn't brought Koji back since that incident, but there is room for him to redeem himself, as Amado has done in Naruto's inner-circle.
It's easy to imagine Koji being brought into the fold, training the likes of Konohamaru and younger warriors even further after their own fight. He does have upgraded and darker techniques than Jiraiya, after all, which could even make him a Ranger like Sasuke. More so, Koji could meet Tsunade now that she's no longer Hokage and start a new romance. She does deserve a fair chance at love and seeing as she isn't bogged down by responsibility anymore -- and is more mature -- it'd be organic to have their souls sensing a spark, with each other as counterpoints.
Naruto would welcome Koji as a clone of his godfather, and with all this knowledge as a soldier, Koji would fit right in in a place that welcomes second chances. He's so uptight but spending time with Tsunade, learning about his predecessor and the dreams Jiraiya had for the ninja world, could all fill the gaping hole in Koji's soul and make him as close to the original as can be. It'd be a very nuanced story, giving Boruto fans something filled with substance while tugging at the nostalgic heartstrings for those who wanted to see Jiraiya and Tsunade's affection truly blossom.