When we want to say that we like something we use 'Dw i'n hoffi'
Dw i'n hoffi caws
I like cheese
Dw i'n hoffi Caerdydd
I like Cardiff
Dw i'n hoffi bananas
I like bananas
On the other hand if we don't like something, we say 'Dw i ddim yn hoffi'
Dw i ddim yn hoffi coffi
I don't like coffee
Dw i ddim yn hoffi Eastenders
I don't like Eastenders
Dw i ddim yn hoffi smwddio
I don't like ironing
To ask someone if they like something, we say 'Wyt ti'n hoffi...?' (informal) or 'Dych chi'n hoffi ...?' (formal). To respond, we say 'ydw' - yes - or 'nac ydw' - no.