True~ It's my fav. OTP so I could be reading between the lines, but you also can't deny all the clues in the episodes before, during, and after their deaths.
Examples: (Before the death) Levi hand picked her himself, and she is the only woman in his squad (also happens to be just a bit shorter than him XD lol. Come on, you can't deny that fact!)
Levi wanted Petra out of danger, and instead to look after the dying solider
(this one being chewed on like a dog bone) While he took on two Titans by himself
. When the solider died asking if he made a difference, Levi gives tells him how he made a difference and his sacrifice will not be in vein. He hears Petra whisper "Captain. He's gone." He looks to Petra for comfort that the man heard what he had to say. "And she says "Yes sir. Just look at him. That's a face at piece."
When they ride their horses, shes always by his side.
Then their was that conversation she had with Auruo (Who always acts like Levi) and he asks, "Your a step early pretending to be my wife. Don't you think Petra dear?" (To me thats a dead give away.)
When Levi made his squad clean their head quarters
(lol), Petra got the least dangerous job of sweeping the floors, instead of hanging and cleaning the windows or standing on stuff to dust.
(This one is optional) When she was talking to Erin, I felt that Levi looked jealous and punished Erin to sweep the floors again (LOL) XD
Then their was the incident where Erin accidentally transformed partially (Right before that happened you see Levi and Petra having a private conversation) and when Levi's squad is on Erin yelling at him, its Petra that shows fear for Levi's safety.
Examples: (during their deaths) You see Levi swinging right past each of his squad members, doesn't stop for any of them ACCEPT Petra. He stops at a branch right above her and you see this look in his eyes (like he isn't sure its real, what he's seeing.)
Examples: (after their deaths) Then when he's attacking the Female Titan
I feel he's releasing all his rage on her, because of his squad of course, but you never see him get this emotional before when he's slayed other titans for killing scouts. It's kind of the same way like when Mikasa attacks become 10 times more violently if it involves Erin.
But Levi still followed orders and retrieved Erin (but first did some bad ass damage on the female titan)
Then theirs the patch scene. You see Levi's squad's bodies laid out in a line and you see one of them has their hand tucked out of their wrapping. It's believed Levi kept Petra's hand sticking out so he would know where her body was, then sat down and took her patch and not the others. Why do you think that is?
Then the next one is when they have titans on their tails. Levi's suggests riding towards the trees, but is denied (you can see how pissed off he is before pulling to the back of the group) and instead has to make the tough decision (Hes gripping his leg, cursing since he can't just fight back instead of what he has to do.) So he orders the bodies to be dumped to save the scouts. You see the bodies rolling, getting stomped on, but its when they slow the pic. down and you see a solder's (the one with the hands sticking out) hood fall back and you see it's Petra. She's the only one you see in the anime/ manga going back and forth between Petra's body falling then this emotional look in Levi's eyes as he watchers her roll away (Not the others).
Then he comforts the solider that screwed them all over because of their thoughtlessness and gives them Petra's badge and saying it was their friends badge, saying, "We can't always carry our fallen comrades home, but we carry their memory's."
(gives the badge) This was Ivan's." (thus he will still continue to carry Petra's memories even without that last piece he had of her)
(he gives that badge one more longing look)
Then finally, when Petra's father is talking to him. I feel its a conversation between a father and the man who has asked for his daughters hand, and the father wants Levi to reconsider. Saying she's devoted to you in 'every-way', but thinks shes too young to be thinking about marriage. And right their, BOOM you see Levi's face that looks absolutely heart wrenching as he's listening and has to tell Petra's father that she died, that he failed to keep her safe and couldn't return her corpse to her family.
Lol sorry if I typed your ear off, but I'm just showing the facts and whats in-between the lines. Oh and the artist was asked if Levi thought Petra was cute and he said> "I think I have portrayed such things between the panels> 40.media.tumblr.com/d195a9b7d4…
So you can chose to believe it or not, I'm still sticking with my belief of Rivetra shipping!!! X3