Good solo class?

I'm a little late but honestly, I'd say either Gladiator or Bishop (debatable). Both of these classes have pretty good survivability throughout the whole leveling process, though I will admit that both do take a bit of leveling before they really start to shine, damage-wise.

If you are soloing, Bishops really suck to level pre-120 these days, though with Bless and Heal 1, you'll be hard pressed to run out of MP or die often. This gets even better post-140 when you have access to Divine Bless and Resurrection. It does still kind of suck to level up pre-180 though since your only attacking magic is Mana Wave and Holy Light and even after getting Nemesis at lvl 180, their damage doesn't really ramp up until lvl 320 when they can get the Judgement passive, though lvl 220's Limit Break does help a bit. After that, it's smooth sailing.

Gladiators are also a bit rough to level pre-180 since they don't have access to Regenerate, which also costs spina to use (Gladiator Revita). Lvl 150's Solid Skin does help out a lot in mitigating damage though. Gladiators are in a bit of a better position after reaching lvl 200 and getting Pillar Blade as a nice AOE damaging skill but even then, they still will have a bit of trouble with MP management until lvl 260 when they get Bloodthirst, which would still require an HP gear set (wouldn't be too expensive to buy or farm some HP+20% though). After that, it's smooth sailing.

This is just my opinion over the question and this is based purely on my experience in leveling these classes from lvl 1 to ~300-340 with little to no spina before leveling the class. With more spina, more classes become good solo classes. Alchemist, for example, can become basically the best solo class with no damage loss with a Resist Set and Damage Disable Set, but I'd never recommend that to any beginner. The class needs waaay too much spina (and time doing production) to reach that point. And of course, with enough spina any class can become a great solo class. But yeah, feel free to correct me if I'm wrong though, I never want to spread misinformation.

TL;DR: Bishop and Gladiator for newbies, in my opinion. If not a newbie and have a lot of spina, Alchemist.

Paladin, why? its easy to use, you will not die so easy early game and when you reach level 140,  you will become a paladin and you can do the skill quest in Elban for an extremely powerful skill called Holy thrust, you can easily hit 150k damage every 2 seconds at level 140 using hp/tank set.

as you pass levels 160, 180, 200, 220, 240 and 260, you will become very tanky and your holy thrust will hit around 600k,

when you are level 360 you will probably hit 1m+

when you reach max level (430) with excellent equipment, your holy thrust will hit 2m damage (3m against dark), while you remain tanky.