Annie prespective:

She has a deep respect for Armin, recognizing his strong will and treating him well. This results in her sparing his life during her rampage, which later allows him to discover her true identity. She admits to not being sure why she did not kill him and is seemingly bothered by his willingness to maneuver her into a trap.

ARMIN PRESPECTIVE 

The two share a mutual respect for each other, expressing admiration for each others' hidden qualities. This causes her to hesitate when attacking in her Titan form, a mistake which allowed Armin to discover her true identity. He then uses emotional blackmail in order to lure her into a trap and facilitated her eventual capture.

Okay despite that I like it in stories very much but this ship is not cannon in the original aot. 

COOMMMMEEEEENNNNTTT!!!!!!!!!!!