If Snikimary did bring a guy home as you suspect, she will not be the first
or the last foreign live-in domestic worker (whether she be Filipino,
Indonesian or Sri Lankan) to do so. But you are not absolutely certain that
she did so. Therefore the question is:Is it fair for you
to fire her?
A live-in domestic worker must be trustworthy if nothing else. You are vulnerable if she chooses to do something undesirable, like stealing from you or bringing a stranger into your home, a stranger who may later return to rob you.
You have two choices: terminate Sniki's services on suspicion or observe her for for a few more days or weeks to either confirm or erase your suspicion. If you choose to fire her, will you be doing her an injustice? If you choose to observe her for a couple more months to be fair to her, are you being fair to yourself?
Suppose you terminate her services. If she can find a new job, she will have lost nothing - except perhaps take a pay cut, if you pay her higher than market. She will probably be happier since she will not be living under a cloud of suspicion. And you will be happier too since you do not have to worry about someone coming to your house uninvited.
If you choose to observe her, it may take a lot more time than you are prepared for. You will have to give her an opportunity to bring a guy home, by going away for the long weekend and telling her when you will be home. Then while you are away in Bintan or Phuket you will be on tenterhooks. When you come home a day earlier in the hope of catching her off-guard, you will face two possibilities: either you have an unpleasant or even violent confrontation with her guest or you are disappointed but still wonder if she is now alerted and has learnt to cover her tracks.
Should you just fire her or wait a month or two? If it so hard to make a decision, in future, if she again offers to compensate you for a dress she burns, just call her bluff and take the money or, more exact, deduct her salary. If nothing else, having to pay for the damage she causes will make her more careful. Hopefully in her disappointment (that you actually accepted her offer) she tenders her resignation.
Or you could instal one of those tiny cameras and monitor the movements in your house from any computer anywhere.
However, ultimately the question you should ask yourself is why in the first
place you are paying for her services? If her presence is no longer required
or welcome, will you still put up with her?