i know they say love is trust but i disagree with this. ciel fully trusts sebastian with his life but he doesn't fully trust sebastian with his heart.
yes, he expresses affection by defending him verbally in the circus/luxury liner arc, trying to help him onto the boat during the lifeboat scene, telling him he did well, etc... but he doesn't want sebastian to know that he's 'weak', that he's human. that's one of the reasons he pushes his friends away, he doesn't want to have to grieve them in front of sebastian. he doesn't want to care about people because he doesn't want sebastian to see him care. it's like how he says he wants to advertise to the orphans so they pressure their parents to buy them funtom toys (what parents ..?). ciel's words at the end of the red butler arc are another example of him deflecting from his kindness.
they also say love is understanding but i also disagree with this. ciel seems to think that sebastian in the manga right now is the same sebastian of season 2.
to explain: ciel thinks showing emotional weakness in front of sebastian will make him look down on him. this impression of him is probably due to the day they met. sebastian also thinks ciel looks down on him and sees him as a dog because of that day. the day they met has caused walls to be put up between them.
to put it succinctly, sebastian and ciel are two characters who have fundamentally misunderstood each other, deeply so.
sebastian knows how kind ciel is and yet he still hasn't been able to figure out the extent of ciel's affection for him. he doesn't understand that when ciel tells him it's okay that he sits in first class in the train and from then on, he always sits in first class, that means ciel doesn't look down on him. when he makes him lie down and eat a shitty porridge, it means he cares. when he says his social status doesn't matter against the double charles, that means he does not fundamentally care for class. when he accepts to take the servants shopping at sebs request and doesn't question where he goes when he stops at somerset house, he is expressing that he believes in him (which is different to trust*).
*ciel doesn't trust sebastian enough to directly express his emotions in front of him. he doesn't, however, think that sebastian will ever intentionally cause him trouble. he trusts sebastian's loyalty as a butler and his aesthetics but not sebastian himself.
when he orders him tea while they sit in a first class dining spot, does sebastian believe ciel when he says it's just because he wants to stretch his legs? do you believe him? from ciel's perspective, he knows that sebastian fundamentally does not like fighting undertaker (because he might lose) but in the manor when r!ciel returned, he tried to. he knows that sebastian didn't sign up for battling against a reaper who wants to bring the dead back to life. as much as he considers sebs cold, he knows agni and sebastian were at least on good terms and saw sebs' reaction to his death. he thinks sebastian isn't capable of being upset about all this. but sebastian is. it's evident from the way he's so snide and harsh on the dinner table towards bard and his expression when lau mentions india. ciel might not think seb is upset/annoyed with this situation but he treats him as though he is.
he treats him with care despite not trusting him, he treats him like a human, despite thinking he's a beast. he doesn't understand him but regardless he shows him compassion. and i think that's higher than a love where you know the person in front of you is good and deserving of your love. if you love someone despite not thinking they're capable of caring for you back and knowing they will destroy you when given the chance (see: green witch arc), do you not think that love is beyond anything built on trust and understanding?
it is the most selfless, altruistic act of love.
sebastian does not know how cared for he is, he only knows that ciel doesn't see him capable of any human emotion (which he does have to some extent, when he said he would compensate modri, that was empathy and guilt), he thinks he's seen as a lowly dog by ciel (but we know ciel likes dogs, as we know sebastian made him feel safe despite being "mean" to him) and he thinks ciel cares about his class, wealth and luxuries (this is the same person who wanted to be a middle class toy maker since he was 9 btw)... and yet he still protects ciel with his life (literally), does everything to ciel's benefit (even when he's not ordered to) and gets him the best clothes to express that he believes in him* (again, misunderstanding ciel's attachment to wealth).
*during the school arc, he has already ordered a tailored version of the cox outfit for ciel because ciel had said he would win. in the current arc, he orders a full set of clothes because ciel said he would get his title back. he believes in him but he doesn't understand him.
hs even tries to get ciel to go out and explore brighton in the recent chapters. but why? shouldn't he want this to be over as soon as possible? no because despite being misunderstood as a beast by ciel, while deep inside he enjoys being a human servant for ciel playing a game with him, he is willing to act like a monster at ciel's behest (green witch arc). is that not a potent form of love? to know you are not understood or trusted but still behaving in a trustworthy way and with good intentions? even though he cannot change ciel's perception of him, he still tries to make ciel happy (remember, he always tells elizabeth that she makes ciel happy, he even questions why she's fighting him in the blue cult arc by saying, "you always wanted to make the young master happy, why are you doing this?" paraphrase). and is that not a higher form of love? to know someone does not trust or know/understand you but loving them anyway? to know they will never see you as a fellow person despite any humanity you show and yet trying to bring them happiness anyway?
it is the most selfless, altruistic act of love.
