How to save [String] to Realm - ios

Question

I am trying to save the JSON response in the realm using Alamofire and ObjectMapper. And I am getting this error:
* Terminating app due to uncaught exception 'RLMException', reason: 'Index 0 is out of bounds (must be less than 0).'
* First throw call stack:
(
0 CoreFoundation 0x00000001113e18db exceptionPreprocess + 331
1 libobjc.A.dylib 0x0000000110984ac5 objc_exception_throw + 48
2 Realm 0x000000010e30efee _Z20RLMThrowResultsErrorP8NSString + 670
3 Realm 0x000000010e310206 _ZL25translateRLMResultsErrorsIZ28-[RLMResults objectAtIndex:]E3$_6EDaOT_P8NSString + 118
4 Realm 0x000000010e310136 -[RLMResults objectAtIndex:] + 102
5 RealmSwift 0x000000010fa37436 $s10RealmSwift7ResultsCyxSicig + 262
6 App Name 0x000000010c0e9155 $s24Mahalaxmi_Life_Insurance12CalculatorVCC14collectionView_22numberOfItemsInSectionSiSo012UICollectionG0C_SitF + 197
7 App Name 0x000000010c0e934c $s24Mahalaxmi_Life_Insurance12CalculatorVCC14collectionView_22numberOfItemsInSectionSiSo012UICollectionG0C_SitFTo + 76
8 UIKitCore 0x00000001155dd2c3 -[UICollectionViewData _updateItemCounts] + 409
9 UIKitCore 0x00000001155dfb4f -[UICollectionViewData numberOfSections] + 22
10 UIKitCore 0x00000001155eafbe -[UICollectionViewFlowLayout _getSizingInfosWithExistingSizingDictionary:] + 511
11 UIKitCore 0x00000001155ed228 -[UICollectionViewFlowLayout _fetchItemsInfoForRect:] + 231
12 UIKitCore 0x00000001155e5dc1 -[UICollectionViewFlowLayout prepareLayout] + 246
13 UIKitCore 0x00000001155dd5a8 -[UICollectionViewData _prepareToLoadData] + 212
14 UIKitCore 0x00000001155ddfb4 -[UICollectionViewData validateLayoutInRect:] + 53
15 UIKitCore 0x00000001155acec6 -[UICollectionView layoutSubviews] + 261
16 UIKitCore 0x000000011620ae69 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1417
17 QuartzCore 0x000000010de75d22 -[CALayer layoutSublayers] + 173
18 QuartzCore 0x000000010de7a9fc _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 396
19 QuartzCore 0x000000010de86d58 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 72
20 QuartzCore 0x000000010ddf624a _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 328
21 QuartzCore 0x000000010de2d606 _ZN2CA11Transaction6commitEv + 610
22 UIKitCore 0x0000000115d5399c _afterCACommitHandler + 245
23 CoreFoundation 0x00000001113482c7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 23
24 CoreFoundation 0x000000011134278e __CFRunLoopDoObservers + 430
25 CoreFoundation 0x0000000111342e01 __CFRunLoopRun + 1505
26 CoreFoundation 0x00000001113424d2 CFRunLoopRunSpecific + 626
27 GraphicsServices 0x000000011971b2fe GSEventRunModal + 65
28 UIKitCore 0x0000000115d2bfc2 UIApplicationMain + 140
29 App Name 0x000000010c0a976b main + 75
30 libdyld.dylib 0x000000011238e541 start + 1
31 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
JSON Response is like this
["Title": [ "S", "Y", "H", "Q", "M" ]]
My Model is like this
class TermList : Object, Mappable {
#objc dynamic var mainTerm : String?
var payingTerm = [String]?
required convenience init?(map: Map) {
self.init()
}
func mapping(map: Map) {
mainTerm <- map["MainTerm"]
payingTerm <- map["PayingTerm"]
}
}