Is it permissible to marry a girl who requests music on her wedding night, with the intention of repenting from this sin after marriage, due to weakness of will and fear of deviance?

If singing at a wedding party is permissible, then it is lawful, and it is recommended to publicize the marriage by beating the daff (tambourine) and with permissible flirtatious poetry. However, if the party includes forbidden musical instruments, lewd singing, or intermingling [of sexes], then it is an objectionable act that must not be condoned. You should search for righteous wives and rely on Allah, for "whoever fears Allah - He will make for him a way out and will provide for him from where he does not expect."