I am trying to tell the guys why I have chosen marketing as my business function. Though my letter is incomplete, what I wanna learn for the moment is that the love and marriage simile too informal for such a letter.

I wrote it in order to give the reader something to remember me.

When considering a career path and hence a business function in particular the right choice is the one that complies with my personal ambitions and my personal traits. My experiences showed me that if people are to achieve outstanding ends in their careers and their personal lifes they should be passionate about the thing they do. This logic is quite simple, as we can not live a happy marriage with a person that we are not in love we can not reach our goals in a company or with a business function that we are not fully devoted to work for.
Hi Karaf,

Whether the metaphor is too informal depends on who the readers are.

If you want to keep it, I'd recommend: Just as you cannot have a truly happy marriage with a person whom you are not in love with, you cannot reach your goals...

and continue to use "you." OR... start with "we" the whole time. But don't switch.
ok thank you. the reader is probably a person from hr department.
Students: We have free audio pronunciation exercises.
Then, no, I would NOT use such a personal metaphor as love and marriage with the HR department.
ok thank u