红炉火 meaning in English

stove fire

The sincere letter that deal says , true gold is not afraid of red ingle , can continue to insist to be done , the strategy that adopts a few correspondence strives for passenger source , be everybody the word of hellion of metropolis believe what one hears
做生意讲的诚信，真金不怕红炉火，可继续坚持做下去，采取一些对应的策略争取客源，不是每个人都会听信坏人的话吧？