***** NOT A TEACHER *****
Hello, Fotogenicas Brasil:
When I read the title of your thread, I immediately thought of the song "Stand by Your Man" by the American singer Tammy Wynette.
Because of very strict American copyright laws, I cannot repeat the lyrics here. (You can easily google them.)
I do believe, however, that I can repeat a few lines:
"But if you love him, you'll forgive him."
"Give him two arms to cling to."
"And show the world you love him."
Ms. Wynette even reminds women that he is "just a man." So don't be surprised by what he does!
In my opinion, then, when someone promises to stand by you, it refers to your first definition: to support you. To be loyal to you -- regardless of what you may do.
Student or Learner