Man

We always need to take lessons from realities of life and study the majority of similar cases before emotionally going ahead with marriage proposals based on promises. Lot of marriages have taken place based on a promise to become a Muslim but ended up with different situations few years after the marriage. Emotions before marriage usually don't last long after marriage. Usually married couples face some issues and misunderstandings between them which can decrease their emotions towards one other. Studying the results of thousands  of similar cases should make us more careful before deciding as such decision is for life. As many similar promises were not fulfilled properly by many, we need to be sure that person has really accepted Islam for the sake of Allah and decided to follow the True religion. His real practice is must and not his promise. After he really practiced Islam like a good Muslim, then you can assess whether he is willing to remain a Muslim for life or just for the sake of marriage.

In fact just promising to be a Muslim will not make permissible for him to marry a Muslim girl, unless he is already a Muslim.

You need to be sure about your future and the future of your children.

Wassalam.

Recommended fast can be broken any time. It is recommended to eat or drink if a Mo'min invite you while your fasting a recommended fast with out telling him that you are fasting.

No need for permission of parents in recommended fast nor in other recommended worship. 

Wassalam.

Yes it is allowed for men to apply henna on hands as tattoo provided that it does not have the name of Allah or any name of The 14 Infallibles according to obligatory precaution. Henna for men should not be like what is usually used by women.

Wassalam.

Every forbidden in Islam is damagingly harmful. We might know little of the harm, but we believe that Allah (SWT) Knows everything and He wants to protect us from its harm.

Wassalam.

It is not permissible to take part in inappropriate topics whether participants are males or females or mixed as far as the topic is inappropriate.

Some special topics for men only or for women only, can be appropriate if discussed among same gender only but are inappropriate if discussed in a mixed group of males and females.

 Muslim must avoid any inappropriate discussion looking not only to the topic but also to the participants.

Wassalam.

Lowering the gaze has been emphasized upon in Quran very explicitly as we read the order of Allah to the Prophet (Tell the believing men to lower their gaze) Sura Al-Noor, verse 30. Same order was given for the believing women to lower their gaze (Sura Al-Noor, verse 31).

Those who remember Allah and obey His orders as obligatory order, Lowe their gaze and protect themselves from looking at sinful scenes.

We have many authentic Hadeeths in this regard which also emphasize on lowering the gaze and the punishment of those do not lower their gaze.

Wassalam.

Muslim man must lower his gaze always and never look at females who are not wearing Hijab. Sitting with non-Hijabi women should not encourage them or give wrong message endorsing their act in neglecting the orders of Allah in Hijab.

Wassalam.

Muslim married man is not allowed to go for Mut'ah marriage with a woman from People of Book (Christian, Joe, Magi) but after permission from his Muslim wife.

Wassalam.

Muslim men have been ordered in Quran to lower their gaze and not look at Nin Mahram women who are not covered by proper Hijab. (Tell the believing men to lower their gaze and protect their private parts (from sinful sexual acts). That is purer for them. (Sura Noor, verse 30).

Next verse says: And tell the believing women to lower their gaze ( from looking at non Mahram men) and protect their private parts.(from sinful sexual acts).(Sura Noor, verse 31).

These orders aim preventing acts which can initiate or cause sinful sexual acts and maintaining the purity and piousness in the hearts of men and women when dealing with each other. It is a type of prevention which is better than cure. Sinful looking initiates sinful desire which can be a step towards sinful sexual act, that is why, lowering gaze has been clearly ordered in Quran and authentic Hadeeths.

Wassalam.