"How do you say 'phrase' in [target language]?" is more often than not a much worse approach than "What would a native speaker of [target language] say if they found themselves in the same situation?".
"What would a native speaker of [target language]
say if they found themselves in the same situation?".
It gets even trickier if you are translating fiction. If you are translating, say, Japanese anime/manga with a Japanese setting for an English-speaking audience you don't necessarily want the characters to sound like Americans or Brits or Canadians or what have you.So you may have to use language that Americans understand, but still make them sound Japanese. Somehow.
I think we take for granted that idioms from other cultures/languages are incomprehensible... often they make a lot of sense when literally translated even if they aren't a "thing" in the language to which they are being translated.
That's also true in English, in my experience. I've never heard someone express this phrase (or a variation) in conversation, but the sentiment is common.
A typical phrasing in English would be more like "She always says she's done but she always comes back."