Hello. what is the best, most reliable website for translating words/phrases?
If I'm pushed, I'd use Bing Translator or Reverso context.
If I'm not pushed, however, I wouldn't use a translator. Ever! They're very inaccurate if a sentence gets a little bit complex. I'd prefer to use dictionaries (I use Le Petit Larousse, or Collins online for French), look up sentence structures, ask questions, but not use a translator!
For bringing this option to my attention (Microsoft is also very busy with automatic translation using deep learning, so might be very interesting) I give you 1 Lingot for that (Microsoft Bing Translator).