"Dwedais i y baset ti'n iawn."
Translation:I said that you would be OK.
Not a construction "that" I have seen before! Another one to add to bod & taw.
So this is using bas- for reported speech, like "would" is used to report an original "will" in English? What did the person originally say? "Byddi ti'n iawn?"
Yes, that's one use for it. And you can use bas- forms for a straightforward conditional as well, as in English:
- Baswn i'n hoffi bwyta. - I would like to eat.
- Basai fe'n mynd i gwrdd â Siôn, ond mae e wedi blino'n lân. - He would go to meet Siôn, but he is tired out.
- Dw i'n siŵr basai hi eisiau dod gyda ni - I'm sure that she would want to come with us.