I knew a man whose fiance caught him messing around in courtship. He attempted dating another woman while planning his wedding but the other woman( I think she was married) reported the matter to his boss in the presence of his fiance the day she visited him in his office.
This other woman did not know the young lady sitting in the office where she lodged complaint was engaged to be married to the man she was reporting. Afterwards, the matter got heated between him and his fiance but they resolved it.
Probably, the matter ended with the promisory note of "I will change when we marry". Unfortunately, the man did not change in marriage. His sexcapades became worse. He lost his life and left his wife and children behind.
It is common to hear people pamper play boys and uncultured girls with statements like "As soon as he marries, he will change".
Dear single, it is unwise to marry someone who promises to change in marriage. If you are privileged to see his/her true colour before marriage, do not allow him/her pin you down with promises like: "I want to marry you because I know you have the power to change me" OR "Once I settle down, I will change".
Marriage is not a rehabilitation program. Do not marry to change anyone, you don't have such powers.
You see he is not committed to God and his kingdom and he is already telling you he will be fervent and committed as soon as he marries you, please run.
Do not let anyone around you use marriage as a bait for change.
Another thing I have seen some adults do is to find a spouse for their irresponsible single relative under the guise of "If he/she marries, he will change". This is wrong. Marriage to such people always end in premium tears.
An irresponsible single will likely be irresponsible in marriage. Who we are is revealed and amplified in marriage not changed. It is the Holy Spirit that changes people not marriage.