Dearie is a homely word of address, often used to a stranger. There you are, dearie, thank you dearie, dearie me.
It is warm from somebody you know and faintly patronising from somebody you do not, which is why it lands so differently depending on who says it. Dearie me is a mild exclamation of dismay and is a separate use entirely.
1noundearieA homely word of address, often used by an older woman to a stranger.
“"Mind the step, dearie," said the old woman as she held the door open for me.”
dearie is a form of address.
From dear + -ie.
Etymology from Wiktionary, CC BY-SA