If truly Newcastle are interested in Ronaldo it will be an offer Ronaldo will accept quickly. Because right now it is not easy for him to see a club that is interested in him. Ronaldo will will prefer to be in Newcastle than Saudi Arabia. Newcastle is not a poor club, am sure Ronaldo would love it.
Ronaldo playing for Newcastle doesn't look possible to me, Newcastle might no be a 'poor' club, but the take over by the billionaires who bought the club is still relatively recent, and it is yet to have any impact on the team. It would be queer to see Ronaldo playing for a club like Newcastle, it would be a new low in his career and i don't think he will be interested in it. If Ronaldo is to stay in Europe, then it has to be a big club that's playing in the CL, if not it's better he leaves for Saudi Arabia knowing his time in the spotlight/elite football is over.