Short answer
Honesty is essential because matrimonial information can directly affect another person's decision to marry.
Islamic Guidance
What Islam teaches
Islam strongly emphasizes truthfulness and prohibits deception. Concealing material information that affects marriage decisions can cause serious injustice and harm.
Practical Guidance
What you can consider
Provide accurate information about age, marital status, education, profession and other important matters. If something significant needs explanation, disclose it respectfully before marriage.
Sources
Qur'an 33:70; Qur'an 2:42.