What is sincerity, and what are the benefits of sincerity?

One of the guys at work was asking me why I became Muslim and I told him it is the path I must follow. I don’t know sometimes what I should say, for me it is the path I must follow. What can I say to someone; I don’t want to push what I believe, so how should I answer someone if asked, what is the right way to answer the questions? Sometimes I feel I don’t give the right answers... Any clues as to what I can say?

I used to be very sinful, my most beloved hobby was to sin. I used to take drugs (hashish, pills, and wine) and I used also to commit adultry.
By Allah’s grace, I repented from the sin of adultry before marriage but the sin of taking drugs remained. It was because of the bad companions I had. Then one of my cousins died, he was of similar age to me. But he was not married, I thought about my situationand that someone who is younger than me has passed away, and we were comitting the same sin togeather, taking drugs.  
Allah has guided me by His grace, so I gave up all sins, I even broke the satellite dish. My life has changed 180 degrees. I became charitable, pray, call people for good and denounce evil, distribute tapes and booklets and attend lectures.
The problem:

I face criticism, starting from family, mother and sisters, that I am strict. They want to listen to songs and watch series on television. If I advise them and say that what they are doing is haram they say: “why is istighfaar (seeking Allah’s forgiveness) prescribed?, If you do not want to listen to songs and watch television then leave, we want to watch and listen” the same problem happens at work as well, I have left home more than one time, my wife stays with them, I take her with me when I leave, but they ask me to let her stay with them. I refuse and my wife feels embarrassed and fears her situation causes any problems. But when I leave her with them, she sits far from TV and from where they sit.  Sometimes I hear my mother making du’aa against me saying: “I wish Allah did not guide you, you made us restless” I seek refuge with Allah from what she says.

My problem at work is, that I work in a military sector, all colleagues are bad, the religious ones are only three, there are six bearded brothers. They get over so many things, the rest of them take hashish and drugs, flirt women and majority are of course smokers.

They all agreed on insulting me, whenever I sit with them, they remind me of my past. They mock the bearded brothers, slander them and describe them as (liers and terrorists) and I feel jealous for them and say: “you are slandering your brothers, they are muslims, you should not mock the beard because it is sunnah to keep it”. Sheikh, they gave me bad reputaion, they always critisize the bearded brothers, they never mention anything good about them.

Is letting my beard grow, abiding by sharia, enjoining good and denouncing evil in this time a crime that I have to pay for, or become immoral like them?
Even my boss, he says: “you bearded men, I will put you under the misoscope, I will not forgive any mistake you do”

I have tried some solutions:
Firstly: I asked to move to another administration, but my request will take some time.
Secondly: I cut my relationship with everyone insulted me by a word or an action. This helped limit the problem. But I do not like this way, as people became careful when they deal with me and fear that anything they say may be disliked by me. So they dislike me and make others dislike me as well.
I wish you provide me with the suitable solution for my problem because I became really tired of it.

Is it permissible for me to say to non-Muslims "And the same to you" when they wish me a Happy New Year or say Best Wishes?

What advice can you give to the Muslims in the west in the current situation in which the Muslim ummah finds itself? How can we fulfil our Islamic duties and please Allaah?.

I am a muslim by birth and I recently got married to a girl who had reverted to Islam. i am from india and many muslims here are very backward in their practices etc.. She was continously asking me questions about my relatives and why muslims are so backward etc.. I lost my temper and I am ashamed to say that in my anger I told her that I was sorry that I was a muslim. I immediately realised my mistake but I said what I said. I am terribly ashamed of myself for saying such a thing. Does this make me a apostate (kafir). I am a muslim and i truly believe in islam in all its glory. I am ashamed and sorry for what I said. Am i a kafir. Do i have to say the shahadah again? Is my nikah nullified as she is still a muslim. Do i have to do the nikah again. Please answer at the earliest. I am really sorry for beingsuch a bad muslim.

I have committed many sins which no one knows of except Allaah. What do I have to do so that Allaah will accept my repentance?

Is it true that anyone who does not accept that kuffaar are kuffaar is a kaafir himself, even if he prays, believes in the Qur'aan, and the Prophet Muhammad? If so, what is the proof for this? Can a person insist on believing that Jews and Christians can be believers and go to heaven after being shown clear evidence against this, and still be considered a Muslim?

please oh brothers could you please tell me how a woman could perform wudu for my wife and also could you please tell me how to say ayat al kursi in arabic words but english text as iam yearning to learn the beautiful ayat which the almighty has mentioned so much about him self.please please could you answer this one asmy heart is yearning for it.
may allah bless our beloved prophet and his family and his companions.

Why does Islam prohibit adoption? Adoption is a good thing. It provides a home, a set of parents, and a loving family to children who otherwise would grow up without such blessings. Why does Islam prohibit children who have no one from belonging to a family?
 

Is divorce issued by a civil court valid?

I don't celebrate Christmas in any way, but my 11 year old daughter loves the beauty of a Christmas tree when decorated. Is it permissible for me to have one in my house throughout the year?