The best way to succeed (in something) is be to passionate about what you do.

To fall in love with what you're doing is the best key to success.

You can be passionate about something without loving it. I have a friend who’s a public defender - and one of the best, but he hates his job. He does it better than anyone, but he’s thinking of going into mediation because he hates the fact that he’s defending horrible people.

KEY!!👍🏼

Russ: Russ: FALLING in love with what YOU DO is the _ key to success.

Added the key. But I still don't know how you can passionate about something and not to love it? Passion is very close to love. Your example is true but rare.
Something tells me that somehow 'passionate' would fit here, too.

PASSION means that you approach something with all your energy, intelligence, effort, etc. You can even HATE someone passionately. It doesn’t mean you love it.

Russ, you need to correct your translation - it’s unnatural.

What is wrong with:
To fall in love with what you're doing is the key to success. ?

as about passionate, 'влюбиться' doesn't necessary mean literally to fall in love. it's little broader. That is why I thought passionate would fit here, too.

To fall in love with what you do is... https://www.google.com/search?sxsrf=ALeKk00hMhf_0Jk3Iehe8bjVlXDPY17Orw%3A1591977202246&ei=8qTjXs_EDtH0tAaWk7DoBg&q=%22to+fall+in+love+with+what+you+do+is%22&oq=%22to+fall+in+love+with+what+you+do+is%22&gs_lcp=CgZwc3ktYWIQAzIGCAAQCBAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeOgkIABCwAxAIEB46BwgAELEDEEM6BggAEAcQHjoECAAQQzoFCAAQgwE6BwgAEIMBEEM6BAgjECc6BQgAEJECOgQIABANOgIIADoHCAAQFBCHAjoECAAQHjoICAAQCBAHEB46BQghEKABOgUIIRCrAlDrgAFYzKEBYLevAWgEcAB4AIABqAGIAZYdkgEFMTQuMjGYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwjPhYWd0fzpAhVROs0KHZYJDG0Q4dUDCAs&uact=5

Falling in love with what you do is... https://www.google.com/search?sxsrf=ALeKk03XLrVdRa_Xd9pJS2A9MZwXCLMt0w%3A1591980656258&ei=cLLjXsyzD_GZwbkPjtmy8Ag&q=%22falling+in+love+with+what+you+do+is%22&oq=%22falling+in+love+with+what+you+do+is%22&gs_lcp=CgZwc3ktYWIQAzIGCAAQCBAeOgkIABCwAxAIEB46CAgAEAgQBxAeUIKiAViZrQFgmsUBaANwAHgAgAFgiAHSBZIBATiYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwjMq4WM3vzpAhXxTDABHY6sDI4Q4dUDCAs&uact=5

Loving what you do is... https://www.google.com/search?sxsrf=ALeKk02c3rmA_aBv5m-eM9i2C3Zs9hdGng%3A1591980682254&ei=irLjXpyQD8OawbkP5t-84Ac&q=%22loving+what+you+do+is%22&oq=%22loving+what+you+do+is%22&gs_lcp=CgZwc3ktYWIQAzIECAAQHjIECAAQHjIECAAQHjIGCAAQBRAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeOgkIABCwAxAIEB46CAgAEAgQBxAeOgYIABAHEB5Q94gBWJWOAWCvkAFoAnAAeACAAW6IAewEkgEDMi40mAEAoAEBqgEHZ3dzLXdpeg&sclient=psy-ab&ved=0ahUKEwic_beY3vzpAhVDTTABHeYvD3wQ4dUDCAs&uact=5

the best key to success -vs- the key to success: https://books.google.com/ngrams/graph?content=the+best+key+to+success%2C+the+key+to+success&year_start=1800&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cthe%20key%20to%20success%3B%2Cc0