- Clarke – The flame will protect me. I don't know how I know, I just... know.
- Bellamy – I believe you.
The relationship between Clarke and Bellamy starts out antagonistic towards each other. In the beginning, Bellamy shows a great amount of animosity towards Clarke and considers her to be one of the "privileged" in the hierarchy the Ark created. Meanwhile, Clarke often disagrees with the decisions Bellamy makes. However, as season one goes on, their relationship develops into a partnership. Their partnership grows into a friendship filled with mutual respect and trust. They are both shown to care deeply for each other and save each others' lives multiple times, often at risk to themselves.
They are separated during the war in We Are Grounders (Part 2), only to be reunited again in the fifth episode of season two. Clarke and Bellamy pull down the lever that causes all the Mountain Men, including the children and people who have helped them, to die in Blood Must Have Blood (Part 2). After that, Clarke leaves Bellamy and the rest of her people behind at Camp Jaha to cope with what happened at Mount Weather and decompress.
In season three, they have been separated and reunited 4 times. In Wanheda (Part 2), Bellamy finds Clarke, captive, but he is stabbed in the leg and she is taken away by Roan. In Ye Who Enter Here, Bellamy arrives at Polis and finds Clarke there. He begs her to come back to Arkadia with him but she refuses so he leaves without her. In Hakeldama, Clarke sneaks into Arkadia to confront Bellamy about his massacre of a Grounder army. He attempts to take her to Pike but she shock-lashes him and escapes. In Nevermore, they are reunited once again and attempt to save Raven's life along with the help of the other Delinquents. In Join or Die, Bellamy admits to Clarke that he was really angry at her for leaving and that he doesn't want to feel that way anymore.
Bellamy and Clarke work together in Season Four. In The Four Horsemen, Clarke is writing the list of people to go into the bunker when Bellamy comes to her side. He tells her that if he's on that list, she's on that list - then, when she doesn't write her own name, he takes the pen and writes in all caps. It is clear that this gesture touches Clarke. In the same episode, Jaha tells Bellamy that Clarke is lucky to have him, and that he "keeps her centred". He responds that Jaha has got it backwards. The two are separated in We Will Rise and reunited at the end of DNR. In the season finale, Praimfaya, Clarke tells Bellamy to use his head and that he inspires people with his big heart. At the end, Bellamy has to decide to leave Clarke behind since she does not make it back to Becca's lab on time. Bellamy, along with six others, use Becca's rocket to go back to the Ark while Clarke remains on the ground. Bellamy assumes Clarke has died in the death wave, and is shown with tears in his eyes, clearly distraught at her death. In an epilogue scene, taking place six years later, it is revealed that Clarke has survived and has been trying to contact Bellamy using a faulty radio. At the end of Season Four it is unclear whether Bellamy has received these messages and is unable to respond or if he still believes Clarke to be dead, but it has been confirmed by Jason Rothenberg and Bob Morley that he has not been receiving the messages and does believe she died in the Death Wave. Clarke radios Bellamy every single day for 2,199 days, just to talk to him, and tells him that he shouldn't feel bad about leaving her behind - he "did what [he] had to do".
- Bellamy and Clarke (The 100) fan spot
- “I got you for that.”
- “Get Clarke whatever she needs.”
- —Bellamy, Earth Kills.
- “We can't lose Clarke. We can't lose her.”
- —Bellamy, Wanheda (Part 2)
- “If you need forgiveness, I'll give that to you. You're forgiven.”
- —Bellamy, "Blood Must Have Blood (Part 2)"
- “I can't lose you too.”
- —Clarke, "Remember Me"
- Bellamy and Clarke are 5 years apart in age.
- In the novel, Bellamy and Clarke have a canon romantic relationship. In the second novel, they confess their love for each other, and at the end of the fourth book, they get engaged.
- In the novel, Bellamy is the one to nickname Clarke "Princess". In the show, Finn is the first one to call her that but Bellamy uses it too.
- We Are Grounders (Part 1), according to John Murphy, Clarke is the Princess and Bellamy is the King in.
- In Nevermore, while Raven was possessed by A.L.I.E., she calls Bellamy "the good little knight by his queen's side" with Clarke being "the queen".
- Their first interaction is in Pilot. Bellamy wants to open the Dropship door, and Clarke warns him that it might be dangerous.
- They are only main characters that appear in almost every episode. Bellamy did not appear in Thirteen and Clarke did not appear in Terms and Conditions.
- In The Other Side script, Clarke aims a gun at Bellamy, threatening to kill him. However, in the script she couldn't shoot him because she didn't want to kill another person she loved. This possibly means that Clarke loves Bellamy, but it is never showed on screen.
- Bellamy saves Clarke multiple times, three times in season 1: he saves Clarke from falling into hole, saves her from getting killed by Dax and Anya. In season 2, when they discover that someone put poison in Lexa's drink, Bellamy slaps the cup out of Clarke's hand. He saves her twice in season 4: shot one of Roan's men who captured her, later Bellamy stabbed grounder ambusher before they could kill Clarke. Bellamy tries to save Clarke in Wanheda (Part 2), but failed.