Tim_MaA_MidB wrote:My fincee will have [...] statements from people in Brazil staying that we have been together for more than 2 years and letter from a company in the UK saying that I have a job with accomodation waiting for me.
That's all evidence that she plans to settle.
You need to decide whether she's visiting the UK for up to six months, or whether she's moving there to live. I know you may want to keep your options open, but immigration people like to put you in their neat little boxes.
If it's a visit, she can travel without a visa, but will need to convince the immigration officer at the airport that she'll be returning home. A return ticket and specific travel plans while in the UK would help there. Evidence of ties to the UK won't help much, and might count against her.
If she's moving to the UK to live, she will need a visa. Showing up without one when it looks like she'll stay would be very risky. At best, she'll be allowed in, but as a visitor and will need to leave the country again within six months. At worst, she'll be sent home on the next plane. You really don't want that to happen.