how a romance began; the start of a love story
Refers to the circumstances or story of how a couple first met and started their romantic relationship. Often used in the phrase 馴れ初めを話す (to tell the story of how one met one's partner).
二人の馴れ初めを聞かせてください。
Please tell me how you two first got together.
彼女との馴れ初めは、友達の紹介だった。
The start of my romance with her was through a friend's introduction.
At my friend's wedding, I asked the couple to tell the story of how they met.
I asked my newly married coworker how she and her husband met.