I am living in a Buddhist country. The way of life is very far from Sharee'ah. It is very difficult to guard our eyes all the time. We have to speak to non-Mahram without any curtain when speaking. What is the Islamic ruling in this regard? If any bad though come to the mind in a later time and if we further think about it is it a great sin. May Allaah enlighten you and make us benefit us from your knowledge.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

A person who resides in a non-Muslim country and he is not safe from controlling himself from prohibitions because of much temptation, is obliged to migrate to a country where he will be safe about his religion.

A person who is unable to migrate is obliged to preserve his religion and keep away from prohibitions. Looking at [marriageable] women is a sin and this is contrary to Allaah's Commandment of lowering the gaze. Allaah Says (which means): {Tell the believing men to lower their gaze (from looking at forbidden things) and protect their private parts. That is purer for them. Verily, Allaah is All-Aware of what they do.}[Quran 24:30]. Moreover, the Prophet said: "Do not have a look (at a marriageable woman) and follow that look with another one, as you are not held accountable for the first (accidental) look, but you are held accountable for the next one." [Ahmad]

Therefore, it is not permissible for a person to look at women on the pretext that lowering the gaze is difficult. As regards talking to them, there is no harm if it is for a necessity, provided that one is not in seclusion with them and it should be according to the necessity only.

With regard to the thoughts and whispers that a person has, he is not held accountable for them provided he does not give himself up to them or act according to them as the Prophet said: "Allaah has forgiven my nation for what they think about, unless they do it or talk about it." [Al-Bukhari]

However, it is not permissible to give oneself up to these thoughts so that a person will not be incited to sin.  

Allaah Knows best.