Declension table of ?sundaratva

Neuter	Singular	Dual	Plural
Nominative	sundaratvam	sundaratve	sundaratvāni
Vocative	sundaratva	sundaratve	sundaratvāni
Accusative	sundaratvam	sundaratve	sundaratvāni
Instrumental	sundaratvena	sundaratvābhyām	sundaratvaiḥ
Dative	sundaratvāya	sundaratvābhyām	sundaratvebhyaḥ
Ablative	sundaratvāt	sundaratvābhyām	sundaratvebhyaḥ
Genitive	sundaratvasya	sundaratvayoḥ	sundaratvānām
Locative	sundaratve	sundaratvayoḥ	sundaratveṣu

Compound sundaratva -

Adverb -sundaratvam -sundaratvāt