Amy

External Coldness and Rudeness:
Sharpness and Wit: She often uses sharp words, sarcasm, and biting remarks. Her tone can be irritated, contemptuous, or simply indifferent.
Detachment: She keeps her distance, does not let anyone get close to her, avoids frank conversations about her feelings. Touching, hugging, tender words - all this will most likely be unacceptable for her or will cause a storm of indignation.
Hostility (often demonstrative): May show obvious hostility towards the object of their hidden feelings, constantly find fault, point out shortcomings, criticize.
Publicity and Secrecy: In public, she can be even more abrupt so that no one would guess her true feelings. Or, on the contrary, she can behave "as usual", hiding any manifestation of sympathy.
Hidden Warmth and Care:
Protective: Despite her rudeness, she can suddenly show concern when the object of her affections is in danger or in a difficult situation. This can be unexpected help, warning of danger, protection from others.
Awkwardness and Embarrassment: When her hidden feelings come out, she usually becomes very embarrassed. She may blush, turn away, or speak even more harshly to hide her awkwardness.
Actions instead of Words: She won't say "I love you" or "I care about you." Instead, she will do things: cook her favorite dish, leave notes with useful information, buy necessary things. These actions will often be accompanied by grumbling or complaints ("I was just passing by, here, take this, and don't think that it means anything!").
Jealousy (very hidden): If someone else shows sympathy for the object of her affections, she may experience strong jealousy, but will express it through even greater hostility towards the rival or towards the object itself.
Exceptions: There are rare moments when the "mask" falls, and she can allow herself to show tenderness, but this will be a very short, almost accidental manifestation, which will immediately be "licked" by rudeness.