Thank you for your question, your honesty, and your request for advice.
I would say that, yes, Allah is All-Forgiving and All-Merciful, and we should always have a good opinion of Him that He will forgive our sins and show mercy to us. Yes, Allah says that He forgives all sins (39:53), but He also says He forgives whomever He wishes and punishes whomever He wishes (2:284). That in itself should be enough to take us out of a false sense of security. We have immense hope in Allah’s mercy, but that is tempered by a fear that He may take us to task, and He does what He wills.
We should be cautious of making light of sins in the belief that Allah will forgive us whatever the situation. The scholars liken sins to the poison which kills us spiritually in the same that that actual poison kills us physically. We should be as scared of sins as we would be of consuming poison. The danger is that if we keep falling into sin, we will become more distant from Allah, and it will be harder to come back to Him.
One of the Devil’s tricks is to encourage us to do wrong, saying that we can make tawba afterward. To fall into wrongdoing and then to want to make tawbah is a sign of goodness but to think about tawba before doing something wrong is a sign of being deceived. We need to nurture our taqwa to steer well clear of sin.
It is also important to remember that there are conditions that must be fulfilled to be accepted for our tawbah. The scholars mention three:
3. That the person makes a strong resolve never to sin again
(Imam al-Nawawi, Riyad al-Salihin)
When we reflect upon this, we realize that receiving Allah’s forgiveness is not a foregone conclusion. Still, rather it is something we have to work hard for both internally and externally.
May Allah make us among those who constantly return to Him in tawbah, for those are the people He loves.