Couldn't agree more. I know of ladies who for the sake of marrying a Muslim BF not only converted to Islam, but even adorned hijab,prayed, started reciting the Quran etc only to abandon it all when their marriages broke down!
On the other hand my hubby originally converted for the sake of an ex, in order to marry her, but Alhamdullilah though their relationship fell apart, he still remained a Muslim and actually became stronger in faith. Similarly I know many gals who likewise remained Muslims though their original intent long ceased to exist.
It is after all up to Allah. But I would advice the OP to first let his intended get to know Islam. Study the faith properly,meet other Muslim converts etc and then decide whether or not she wishes to actually convert.There should be no compulsion in religion.
And finally a Muslim man can marry a Christian or Jewish lady without her having to change her faith.