Please help me find this Cdrama

romance story. 

female lead study aboard and come back to china.

  join business where male lead is boss. they are classmate before she went aboard. 

there are kidda love triangle but not really, female send wrong love letter to other guy. 

this is only information I remember.

please help! Thank you very much!

 Div:

I'm not sure but is it Le Coup de Foudre?

in Le Coup de Foudre Male lead goes abroad and becomes boss of fml

 Saygo :

Is it Here to Heart? 

i think so too