The gem's alright, but you do need to do your valentine daillies everyday and not get unlucky to get it, as far as I can tell. I already missed a day cause I didn't bother going there first day. You can buy more roses from the cash shop but... yeah.
Current gem setup would be, attack power diamond(highest priority, worth spending the 25g to get a +25 one over upgrading weapon past true profane as it's a bigger damage increase), lifesteal amethyst, damage on crit ruby and a last gem which would probably be the new one for 3attack power, since nothing else is really that good. The heal on evasion is mostly irrelevant, although it can help for soloing or if you're tanking.
And the attack power is always active, only the heal requires an evasion, to poster above.