Why the small little white flowers get dark and drop fast,
is each have small life time.
Can it grow all time indoor with no sun

Carmona produce many tiny flowers and these do have a short life - this is entirely natural. They will only produce seed if cross pollinated with another tree of the opposite sex.
They can be kept outdoors in summer (minimum 50 F) but are known to prefer a fairly constant temperature - they will do OK on a well lit windowsill indoors, sunlight is essential. Use a free draining soil, keep moist, they like humidity too so a gravel tray under the pot is sometimes beneficial. Mine lives quite happily in our bathroom.

Dave

Thank you so much Dave that was beneficial .. Mine is in my bathroom too
It is well lit near the window but never reach the sun rays... is that would be a problem?

Is it would be better to cross pollinated with another tree

Karimsaadmohamedsaad wrote:

Thank you so much Dave that was beneficial .. Mine is in my bathroom too
It is well lit near the window but never reach the sun rays... is that would be a problem?

No, that's not problem, in front of a window is a good thing so the tree gets enough sunlight, remember to turn it after a while so all sides get sun.

Yes, forgot to mention about turning it round, once a week will do. You only need to pollinate if you want to grow seeds, I don't know how you tell whether a tree is male or female though..
Keep it close to the window to get most benefit from daylight, direct sun shouldn't be needed all the time.

Dave