Want to apply Chinese visa

I'm Filipina, I have fiance in China, we planning to get married in PRC.. Now I'm here in the Philippine, I want to go Singapore for tourist. If I want to apply Chinese entry permit at PRC embassy in Singapore is it possible even I'm a tourist in Singapore?? I tried to apply here in the Philippine but I deny and I dunno what is the reason, the embassy here in Philippine didnt give me any reason why! Is there any possibility for me to apply for it even if I'm tourist in Singapore??