Shaykh Al Uthaymeen said:
“Similarly from that which is important is that the individual, it shouldn’t make him happy that the people accept his statement (just) because it is his statement. Rather it should make him happy that the people accept his statement if he sees it to be the truth because it is the (fact that it is the) truth, not that it is his statement.
Similarly it shouldn’t sadden him that the people reject his statement because it is his statement because then he has called to himself.
Rather it should sadden him that they reject it because (i.e. while) it is the truth and with this, sincerity would be made a reality.
Thus sincerity is extremely hard, except that if an individual directs himself towards Allah a truthful, safe inclination upon the straight path, then Allah will aid him upon it (sincerity), and make it easy for him.
[Qawlul Mufeed 81]
Majid Jawed Al-Afghanee