Present tense ?

You use present tense when something is happening that exact moment. You made that realization before and not that second, right?

VisnjaYou made that realization before and not that second, right?

I am sorry . I don't understand "not that second " mean ...
Yes . I made that realization before I speak . So I should speak it in past tense ?
" I never knew what real happiness was until my parents left me , but by then it was too late ." This is the correct way to say ?

I mean by this second, you don't make realization this instance. If I were you, I would probably say it that way. To put it more plainly, your parents left and then you realized something. Your parents are not leaving now when we speak, they left before that, right? That's why that is in the past tense. Their departure made you realize what happiness is. And another reason why I suggest that it is

"and your understanding of what happiness is."

Very well done

outrageousIn normal conversation, can I speak in present tense ?

Of course, but why would you tell the story of what happened in the past by using the present tense? The following sentence, in the present tense, makes no sense.

I never know what real happiness is until my parents leave me, but by then it is too late.

That means your p

VisnjaYour parents are not leaving now when we speak, they left before that, right?

Right ! All that happened in the past .

VisnjaTheir departure made you realize what happiness is. And another reason why I suggest that it is past tense it's because of this regret I sense in the last part "... but by then it was too late". Regret that y

CalifJimBut I think you want to say that your parents left you one time, not that your parents often leave you again and again.

Wow, English is amazing.