The first "a" sound is short, like in "and", while the second one is long like in "marble". It's worth noting that the "beauty" in question is the characteristic, not the person who has the characteristic. The Arabic equivalent meaning "beauty = beautiful" is "Jamil" where the "a" sound is short and the "i" sound is long like in "seed". No, it doesn't specifically mean "God's beauty", neither does "Jalal" mean "God's wrath". "Jalal" doesn't even mean wrath to begin with but is closer to "greatness/highness". And all these comments talking about "ghetto people selling drugs" are both funny and sad at once.
The name Jamal means "God's beauty or God's mercy." It is the opposite of the name Jalal which means "God's wrath." It is originally an Arabic name and used commonly among Muslims. The female form of Jamal is 'Jamala' and is quite popular. It may also be spelled as 'Jemal' or 'Jemala.'