As they have already said xx means kisses. You can also see "xoxo" which means kisses and hugs :)

My friend from the UK uses it a lot in messages to his Ukrainian girlfriend. He explained me that 'XXX' means 'kisses' (an expression of his love), and 'xx' is an expression of the friendship.

Yes, kisses, each X means a kiss, we use them when we write to our partners, friends and relatives.

It means "kiss kiss". Lucky you! :D

Thank you! Now it's clear how to use it and not to find myself in embarrassing sitiation ;)