I'm not sure what did you really mean by "ssuai" for you.
Never mind, but it could be
- beautiful : สวย (suay) [ 수우아이] if you read following what i write in korean, read it in one shot, and don't accentuate the "이" at the end. For this word, the tone you should pronounce must be deep, if not, it would be
- unfortunate / bad luck / unlucky : ซวย (suaiii) [수우아이 ]
These words seem quiet similar or maybe the same for foreigners but in thai, these words aren't spelled in the same way, and the tone you should pronounce for this one must be soft.
- help : ช่วย (shuaii) [ 츄아이 ] for this one, just like the 2 i've mentioned above, don't accentuate the "이" at the end. Soft or deep sound doesn't matter for this one, what's important is that you have to accentuate the last syllable
Like, 추 (normal) 우아이 (accentuate)
By the way, when i say that you shouldn't accentuate the "이" at the end mean that, you shouldn't read it like
추/우아/이 , just go with the flow, I'm sure you get what i mean hahahah. Hope it helps you a bit.