Giyu Tomioka from Demon Slayer is the current Water Hashira from the anime/manga series. He is a man of strong equanimity who always has a stern and calm expression. He is also shown to have a strong sense of justice and is a very responsible person. He isn't open compared to most of the Hashira in the anime, but he is no less powerful.
Characteristics like these often make fans wonder whether Giyu Tomioka has a love interest in Demon Slayer. The answer is no, Giyu Tomioka does not have a love interest explicitly mentioned in the manga; however, fans have gathered an angle on Shinobu from the anime.
Disclaimer: This article contains spoilers from the manga/anime.
Fans' deduction on Giyu Tomioka and Shinobu Kocho's love angle from Demon Slayer

Giyu Tomioka and Shinobu Kocho from Demon Slayer are Hashira under the Demon Slayer Corps. They first appeared together during the Mount Natagumo arc when they were dispatched to fight against the Lower Five demon Rui and his demon family. Thereafter, certain interactions between Giyu and Shinobu are interpreted by fans as romantic.
However, there were no such explicitly romantic moments in either the anime or manga. The story simply states they are friends and colleagues, as mentioned in the storylines. Shinobu was seen to fairly tease Giyu throughout the anime, while Giyu, being stoic, didn't have many conversations with her.
During the Tsuzumi Mansion arc, there is a confrontation between Giyu and Shinobu that is filled with tension and unspoken emotions. Shinobu is seen admiring Giyu's strength and resolve, while Giyu shows deep respect for her dedication and tragic past.

Subtle moments during the Mugen Train arc might have led to such beliefs by fans. Incidents like Shinobu trying to understand Giyu's stoic nature and teasing him occasionally while also respecting his decision-making, are other key factors that night that have led to fan speculation.
Other relationships in Giyu's life that he treasured from Demon Slayer

Giyu, being a guy of stoic nature, rarely opened up to anyone from the series. His introverted nature also played a key factor in why some of his comrades didn't want to converse with him. However, Giyu did treasure some people in his life who repaid him with kindness and support throughout.
Sabito
Sabito was a friend Giyu treated even after his death. Sabito and Giyu shared a strong friendship while training under Sankonji Urokodaki, as they both had a tragic past and shared a similar experience with demons. Unfortunately, Sabito died in a tragedy, while Giyu survived. Upon Sabito's death, Giyu was seen to have been filled with guilt and grief.
Sankonji Urokodaki
Sankonji Urokodaki, the former Water Hashira and Giyu's teacher, had a relationship with Giyu based on respect and guidance. Sankonji trusted Giyu to the extent that he accepted Giyu's decision to shelter Tanjiro and Nezuko and train him. Urokodaki showed great trust in his former student, Giyu.
Tsutako Tomioka
In a brief appearance during a flashback in the Hashira Training arc was Giyu, revealing Tsutako Tomioka's story to Tanjiro. Tsutako was Giyu's older sister. Giyu recalled how Tsukato sacrificed herself to keep him safe the night before her wedding. The guilt of his sister's sacrifice would often make Giyu contemplate suicide and question his existence until Sabito helped him conquer these thoughts.
Tanjiro Kamado
Giyu and Tanjiro met in the very first episode of the Demon Slayer anime when Giyu interfered with Nezuko, a recently turned demon attacking Tanjiro. Giyu trusts Tanjiro and spares Nezuko, which turns out to be a great decision. Ever since Tanjiro and Giyu shared a bond where they cared for and respected each other, a bond that lasted until the very end.
Final thoughts

Giyu Tomioka and Shinobu Kocho had a relationship that was friendly and never romantic. There were certain subtle incidents from the anime that showed signs of it progressing further, but it was never implemented. Being a guy of introverted nature, he barely had anyone he could trust who loved and cared for him in return.
Although a lot of people he cared for and who cared for him got lost, Giyu and Tanjiro are two of the best examples of bonding from the anime. With the Infinity Castle arc right around the corner, fans await Giyu's story inside the Infinity Castle. He, alongside other Hashira and demon slayers, is set to take on Kibutsuji Muzan and the other Upper Rank demons in the final battle.
Also read:
- Demon Slayer: Who is Zenitsu Agatsuma?
- 10 best anime movies to watch while waiting for the Demon Slayer Infinity Castle Arc trilogy
- Demon Slayer Arcs: The Complete List of All 12 Arcs