Yes, Singapore is a very safe country. You generally don't have to worry being robbed along the streets and its a very clean country. I'm actually a Singaporean myself

and I think that its quite a nice country for families to visit. People are fluent in English, so they'll not be much problem in communication.
I've been to Thailand, namely Bangkok and Pattaya and I feel that its a nice place to go too. I'll definitely visit Thailand again when I have the chance. Bangkok is a very nice place to shop at since the stuffs there are relatively much cheaper (for me) and Pattaya was an eye-opener cause of the difference in culture.